Is it 256 with full path, or 256 just for the filename?
If filename, in dos:
dir /s | sort /+275
or
dir /s | sort /+275|more
will show you the files. They'll be at the very top (hence the |more to stop it at the beginning) or very bottom (so you want to see the end, no |more). It won't give the path, but you can then search out the specific files with another dir /s for their exact names.
(I'm guessing on the number, it's 256 plus the offset, which IIRC is 20, so I subtracted one to be on the safe side)
If it's full path,
attrib /s |sort /+256
or
attrib /s |sort /+256|more
(same as above, only this time no offset and you'll know the full path)