2. Video Options
3. Mode: Windowed (I guess selecting that should switch to Fullscreen)
4. Immediate SIGSEGV
md5sum vox: 8b36d1948b1a8174c9c8f29bd1446364
Platform: Linux 3.4.7 amd64
There is no amd64 build (*hint hint* *puppy-eyes*) and I don't have a 32-bit debug libc, so I preloaded. Looks like you are trying to memcpy() to NULL:
Program received signal SIGSEGV, Segmentation fault.
#0  0xf7ed2111 in ?? () from /lib32/libc.so.6
#1  0xf7fdbc84 in memcpy (dest=0x0, src=0xf51dd008, n=12800) at vox_dbg.c:15
#2  0x080aa41e in codo_blit_to_video ()
#3  0x080a942f in codo_blit ()
#4  0x08095697 in codo_blit_back_page ()
#5  0x08094337 in codo_main ()
#6  0x080499fb in main ()
Core file from a non-preloaded run + libc is here (about 6 MB download).
Looking at the Support forums, nobody else seems to have this problem. So if there's anything I can do to help track it down, just holler.
I had a similar crash while trying out different window managers under ubuntu. Using Cinnamon, and switching between windowed/full at unusual resolutions causes the same crash because SDL starts returning NULL for the screen's pixeldata.
For now it's also possible to use an opengl blitter which sidesteps the problem. Look in ~/.lexaloffle/Voxatron/config.txt and set open_blit to 1