Looking at the linenumbers, there is a version mismatch between your module and mine :-)

Nevertheless, the lines in question are almost certainly:

sub _USER { shift->command('USER',$_[0])->response() == CMD_OK }
sub _PASS { shift->command('PASS',$_[0])->response() == CMD_OK }
[download]

shift->command() returns the object itself, calling response() to fetch the , well, response.

Looking at Net::Cmd::response() shows, that it will return undef if the response from the server can't be parsed.
I would manualy play through the commands via telnet server 110 to see what's going on, and have a deeper look at POP3.pm and Cmd.pm than my quick glance now.

regards,
tomte

---

Hlade's Law:

If you have a difficult task, give it to a lazy person --
they will find an easier way to do it.