It is a very common practice (and one you'll even find demonstrated in Programming Perl, the Camel book) to put a  1; as the last line of your module so that the module returns true. Try it and see if that clears up your problem.

Update: To clarify, I just wanted to quote the relevant statement out of Advanced Perl Programming (the Panther book):

When a file is require'd or use'd, it is expected to return a Boolean success value (zero for failure, nonzero for success). That is, the last executing statement at global scope must be a statement such as "return 1;" or just "1;". Note that this is not necessarily the last statement in the file; it is just the last executing statement.