Failed backup due to corrupt (and unlocatable) file

[ewing1871]

Time Machine has been failing to backup due to an error that reports an attempted backup of 1230754.5 MB (the actual size is less than 42 GB) that is too large to fit on the 250 GB hard drive.

I found these errors in the console:

3/31/08 3:42:33 PM FindSystemFiles[173] Finding system files...
3/31/08 3:42:33 PM [0x0-0x17017].com.apple.systempreferences[169]
2008-03-31 15:42:33.360 FindSystemFiles[173:613] Finding system files...
3/31/08 3:42:45 PM FindSystemFiles[173] FSOpenIterator failed
3/31/08 3:43:01 PM FindSystemFiles[173] WARNING: Couldn't determine
size for /Applications/Utilities/Boot Camp Assistant.app
3/31/08 3:42:45 PM [0x0-0x17017].com.apple.systempreferences[169]
2008-03-31 15:42:45.303 FindSystemFiles[173:613] FSOpenIterator failed
3/31/08 3:43:01 PM [0x0-0x17017].com.apple.systempreferences[169]
2008-03-31 15:43:01.668 FindSystemFiles[173:613] WARNING: Couldn't
determine size for /Applications/Utilities/Boot Camp Assistant.app
3/31/08 3:48:45 PM FindSystemFiles[173] WARNING: Couldn't determine
size for /private/etc/mach_init_per_user.d
3/31/08 3:48:51 PM FindSystemFiles[173] Writing system path cache.
3/31/08 3:48:51 PM FindSystemFiles[173] Error writing cache to /
Library/Caches/com.apple.SystemMigration.plist
3/31/08 3:48:45 PM [0x0-0x17017].com.apple.systempreferences[169]
2008-03-31 15:48:45.586 FindSystemFiles[173:613] WARNING: Couldn't
determine size for /private/etc/mach_init_per_user.d

I'm guessing this is the problem, but I can't find the files. I'm working on my employer's computer who says she deleted the Boot Camp app last month, but a search about Boot Camp says it should be uninstalled from within the program. Neither file are in the location the console gives, and I've tried looking for invisible files but have had zero luck.

Does anyone have any ideas?
Thanks.