Whilst talking to Mental, I noticed one thing about the Boehm-GC libs that might be a problem on Win32. gc6.2 and gc6.3 have similarly-named .h files in their include directory, but they are in -different places-. This means that an upgrade from 6.2 to 6.3 will not overwrite the .h files, and a mismatch between the .h definitions, and the actual object in libgc.a, is very possible.
To reduce the number of candidate sources of bugs in GC by one more, I have repackaged gtk24.zip to contain only the .h files supplied by gc6.3.
The cleaned-up gtk24.zip is here: http://troi.hous.es3.titan.com/~rjamison/inkscape/gtk24.zip ...and a complete rebuild of Inkscape is here: http://troi.hous.es3.titan.com/~rjamison/inkscape/builds/Inkscape0409010635....
Again, I am not saying that this is going to fix the problems, but as Forrest Gump would say, "that's one less thing."
Bob