I'm having an issue where xbmc will crash when in the process of transferring files to the xbox's hard-drive. I finally did two things as this has been a problem for a little while. My FTP client of choice has been FileZilla. Either for Windows XP/Vista, or Debian Linux.
1. Left the debugging mode on. (the onscreen text can get annoying after a while)
2. Found a file that consistently caused a crash when ftp'ing.
Towards the bottom of the debug log file, I noticed this.
FATAL: EXCEPTION_ACCESS_VIOLATION (0xc0000005)
I've zipped up both log files, and uploaded them HERE.