Crash on exit? (MacOS FF 2.004)

Since the upgrade to FF 2.004, I've been having troubles with FF not exiting cleanly (running standalone on MacOS).
After selecting 'Quit', the FF window disappears, but the process remains and sits there on 100% CPU for ages.
If you have the patience to wait, it eventually crashes.
Here's the top of the crash report which might be useful:

Process: Filter Forge [4131]
Path: /Applications/Filter Forge 2/Filter Forge.app/Contents/MacOS/Filter Forge
Identifier: com.FilterForge.FilterForge2
Version: ??? (2.0)
Code Type: X86 (Native)
Parent Process: launchd [81]

Date/Time: 2010-04-02 02:50:37.414 +1100
OS Version: Mac OS X 10.6.3 (10D573)
Report Version: 6

Interval Since Last Report: 167904 sec
Crashes Since Last Report: 3
Per-App Interval Since Last Report: 123620 sec
Per-App Crashes Since Last Report: 2
Anonymous UUID: E30BE93B-535A-4B2B-B81C-0F2F0666855C

Exception Type: EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0x0000000001400160
Crashed Thread: 0 Dispatch queue: com.apple.main-thread

Thread 0 Crashed: Dispatch queue: com.apple.main-thread
0 libSystem.B.dylib 0xffff1289 __longcopy + 137
1 libSystem.B.dylib 0xffff0876 __memcpy + 214
2 libstdc++.6.dylib 0x96cd8a4f std::string::_Rep::_M_clone(std::allocator<char> const&, unsigned long) + 89
3 libstdc++.6.dylib 0x96cd8b40 std::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(std::string const&) + 36
4 com.FilterForge.FilterForge2 0x0075142f std::_Rb_tree<unsigned int, std::pair<unsigned int const, unsigned int>, std::_Select1st<std::pair<unsigned int const, unsigned int> >, std::less<unsigned int>, std::allocator<std::pair<unsigned int const, unsigned int> > >::insert_unique(std::pair<unsigned int const, unsigned int> const&) + 5057
5 com.FilterForge.FilterForge2 0x0074f74d std::basic_string<char, std::char_traits<char>, std::allocator<char> > std::operator+<char, std::char_traits<char>, std::allocator<char> >(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) + 951
6 com.FilterForge.FilterForge2 0x0074675f XFW::Helpers::CheckFailed::clone_object() const + 1987
7 com.FilterForge.FilterForge2 0x0053bc10 CGContext* Controls::get_event_parameter<CGContext*>(OpaqueEventRef*, unsigned long, unsigned long) + 3934
8 com.FilterForge.FilterForge2 0x0053bd67 CGContext* Controls::get_event_parameter<CGContext*>(OpaqueEventRef*, unsigned long, unsigned long) + 4277
9 libSystem.B.dylib 0x95ff33bf __cxa_finalize + 208
10 libSystem.B.dylib 0x95ff32d4 exit + 33
11 com.FilterForge.FilterForge2 0x0000272f 0x1000 + 5935

Thread 1: Dispatch queue: com.apple.libdispatch-manager
0 libSystem.B.dylib 0x95ffab42 kevent + 10
1 libSystem.B.dylib 0x95ffb25c _dispatch_mgr_invoke + 215
2 libSystem.B.dylib 0x95ffa719 _dispatch_queue_invoke + 163
3 libSystem.B.dylib 0x95ffa4be _dispatch_worker_thread2 + 240
4 libSystem.B.dylib 0x95ff9f41 _pthread_wqthread + 390
5 libSystem.B.dylib 0x95ff9d86 start_wqthread + 30

Thread 2:
0 libSystem.B.dylib 0x95ff3286 select$DARWIN_EXTSN + 10
1 com.apple.CoreFoundation 0x9834c82d __CFSocketManager + 1085
2 libSystem.B.dylib 0x96001a19 _pthread_start + 345
3 libSystem.B.dylib 0x9600189e thread_start + 34

Thread 0 crashed with X86 Thread State (32-bit):
eax: 0x00026000 ebx: 0x00000000 ecx: 0x00c7ee58 edx: 0x00040000
edi: 0x26bc1040 esi: 0x013d9960 ebp: 0xbffff6cc esp: 0xbffff6c0
ss: 0x0000001f efl: 0x00010206 eip: 0xffff1289 cs: 0x00000017
ds: 0x0000001f es: 0x0000001f fs: 0x00000000 gs: 0x00000037
cr2: 0x01400160

sample from when it hangs before the crash:
Sampling process 76211 for 3 seconds with 1 millisecond of run time between samples
Sampling completed, processing symbols...
Analysis of sampling Exited process (pid 76211) every 1 millisecond
Call graph:
1763 Thread_1779469 DispatchQueue_1: com.apple.main-thread (serial)
1763 0x272f
1763 exit
1763 __cxa_finalize
1763 CGContext* Controls::get_event_parameter<CGContext*>(OpaqueEventRef*, unsigned long, unsigned long)
1763 CGContext* Controls::get_event_parameter<CGContext*>(OpaqueEventRef*, unsigned long, unsigned long)
1762 XFW::Helpers::CheckFailed::clone_object() const
1730 std::basic_string<char, std::char_traits<char>, std::allocator<char> > std::operator+<char, std::char_traits<char>, std::allocator<char> >(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)
1730 std::_Rb_tree<unsigned int, std::pair<unsigned int const, unsigned int>, std::_Select1st<std::pair<unsigned int const, unsigned int> >, std::less<unsigned int>, std::allocator<std::pair<unsigned int const, unsigned int> > >::insert_unique(std::pair<unsigned int const, unsigned int> const&)
1730 std::_Rb_tree<_opaque_pthread_t*, std::pair<_opaque_pthread_t* const, XFW::Threading_Platform::ThreadInfo>, std::_Select1st<std::pair<_opaque_pthread_t* const, XFW::Threading_Platform::ThreadInfo> >, std::less<_opaque_pthread_t*>, std::allocator<std::pair<_opaque_pthread_t* const, XFW::Threading_Platform::ThreadInfo> > >::find(_opaque_pthread_t* const&)
30 XFW::Kernel::StdException::clone_object() const
26 XFW::Kernel::StdException::clone_object() const
20 dladdr
20 dladdr
16 ImageLoaderMachOClassic::findClosestSymbol(void const*, void const**) const
3 ImageLoaderMachOCompressed::findClosestSymbol(void const*, void const**) const
1 dyld::findImageContainingAddress(void const*)
4 XFW::TypeCastError::clone_object() const
4 XFW::TypeCastError::clone_object() const
2 vswprintf
2 __vfwprintf
2 __xfputwc
1 __sfvwrite
1 __xfputwc
1 free
1 szone_free_definite_size
1 wcslen
1 XFW::Kernel::StdException::clone_object() const
1 XFW::Threading::MutexedObject<XFW::Threading_Platform::ThreadStartupInfo, XFW::Threading::FastMutex>::MutexedObject()
1 __cxa_demangle
1 d_demangle
1 d_type
2 write$UNIX2003
1 dyld_stub_operator delete(void*)
1 std::basic_string<wchar_t, std::char_traits<wchar_t>, std::allocator<wchar_t> >::basic_string(wchar_t const*, std::allocator<wchar_t> const&)
1 wchar_t* std::basic_string<wchar_t, std::char_traits<wchar_t>, std::allocator<wchar_t> >::_S_construct<wchar_t const*>(wchar_t const*, wchar_t const*, std::allocator<wchar_t> const&, std::forward_iterator_tag)
1 std::basic_string<wchar_t, std::char_traits<wchar_t>, std::allocator<wchar_t> >::_Rep::_S_create(unsigned long, unsigned long, std::allocator<wchar_t> const&)
1 operator new(unsigned long)
1 malloc
1 malloc_zone_malloc
1 szone_malloc_should_clear
1 small_malloc_from_free_list
1 small_free_list_add_ptr
1 XFW::Graphics::RectangleTreeItemNotFound::clone_object() const
1 XFW::TypeCastError::clone_object() const
1 XFW::TypeCastError::clone_object() const
1 vswprintf
1 __vfwprintf
1 __xfputwc
1 __memcpy
1 XFW::TypeCastError::clone_object() const
1 XFW::TypeCastError::clone_object() const
1 vswprintf
1 __vfwprintf
1 __xfputwc
1 __sfvwrite
1 reallocf
1 realloc
1 malloc_zone_realloc
1 szone_realloc
1 szone_size
1 XFW::TypeCastError::clone_object() const
1 XFW::TypeCastError::clone_object() const
1 std::valarray<wchar_t>::valarray(unsigned long)
1 operator new(unsigned long)
1763 Thread_1779477 DispatchQueue_2: com.apple.libdispatch-manager (serial)
1763 start_wqthread
1763 _pthread_wqthread
1763 _dispatch_worker_thread2
1763 _dispatch_queue_invoke
1763 _dispatch_mgr_invoke
1763 kevent

Total number in stack (recursive counted multiple, when >=5):
8 XFW::TypeCastError::clone_object() const

Sort by top of stack, same collapsed (when >= 5):
kevent 1763
std::_Rb_tree<_opaque_pthread_t*, std::pair<_opaque_pthread_t* const, XFW::Threading_Platform::ThreadInfo>, std::_Select1st<std::pair<_opaque_pthread_t* const, XFW::Threading_Platform::ThreadInfo> >, std::less<_opaque_pthread_t*>, std::allocator<std::pair<_opaque_pthread_t* const, XFW::Threading_Platform::ThreadInfo> > >::find(_opaque_pthread_t* const&) 1730
ImageLoaderMachOClassic::findClosestSymbol(void const*, void const**) const 16
Sample analysis of process 76211 written to file /dev/stdout
sampleTask: task_threads (?/?) (ipc/?) unknown subsystem error (12e6ae9a)

Excellent, thanks!
Serves me right for grabbing it straight away!