Perl handles UNCs just like any other program under Win32. When people have problems with them, it usually has to do with a poor understanding of how to use quotes in Perl.

The user has to be logged into the remote machine for this to work. I've found that UNCs are particularly problematic when connecting to a Novell server (Novell 3.x anyway) from Windows NT. Even when the user is logged in and UNCs work in Windows applications, they don't always work from Perl and require using a module to explicitly map a network drive to connect.