I agree. When I read your inital comments I immediately thought you might be running this on a Win32 system. The Mail::Audit module is attempting to use the getpwuid function which isn't supported on Win32. In this case you might be able to alter the Mail::Audit module on your system manually to work around this problem. If you read through the source code for Mail::Audit the module makes several calls to the getpwuid function. Try and amend these few lines to make them Win32 compliant and then re-run your script.