3 ideas :
your webserver is typically under a different user id ("nobody"), and may (will) have different permissions to that particular directory.
I think that the path in use lib needs to be quoted : use lib '/home/benjamin', but I could be wrong.
also, you may be interested to see if your command line and web server are looking at the same perl : which perl may reveal discrepancies.

and, uh, use strict. and diagnostics... *cough*