Can anyone give me tips to fix this error? or Is their something wrong with my PERL?

HTTP/1.0 500 Perl execution failed Server: MiniServ/0.01 Date: Fri, 30 Mar 2007 22:49:52 GMT Content-type: text/html Connection: close
Error - Perl execution failed

Illegal modulus zero at ./mailboxes-lib.pl line 477.