I've already resigned myself to go the substring method, but just so you guys understand why the spec is laid out as it is:

The user initiates a file transfer. This is a bunch of files that have been updated or created by said user. The files are programmatically zipped up for transfer to a server (to minimize bandwidth) where they become automatically available for all the other users that need this update.

Part of the zip process is to select or create a directory predetermined by the original user (so the unzipping process will put the files in the correct place). Since these files generally go into a not-yet-created directory, the user gets to change the suggested one to anything he/she wants.

Hence the need for error checking.

Thanks, guys, for attempting to help.