The trash under OSX just won't empty, whenever I try to empty trash, I get an erroneous error, and then it stops deleting, w/o ever deleting a thing, even if I click on "continue" w/ the window that pops up.
I had the same problem when I deleted a locked file. My problem was confounded by the fact that the file resided on a partition other than that of my user account. If you trash something from the same partition it will appear in a hidden directory, ~/.Trash, at the root level of your home directory. On the other hand, if you trash something on another drive, it will be moved to /.Trashes at the root level of that drive.
In any case, if you can find the file you can fix it with ResEdit under OS9 (or Classic). From the ResEdit file menu choose "Get File/Folder Info..." and select the locked file(s), de-select the "File Locked" switch, close the info dialog and trash away.