Since Panix changed to using SquirrelMail, an extra step is required at the Panix web site for the RW4M Initial Setup Wizard to work. Before using the Initial Setup Wizard, log into the Panix webmail page at https://mail.panix.com. Click on Options, then Mail Forwarding Options. Enter the following (on one line):
|exec /usr/local/bin/procmail||exit 75
That is not enclosed in quotes. Hit the Submit button on that page.
In the RW4M settings dialog, select the option that reads: I do not need a .forward or .qmail file. The FTP host is ftp.panix.com.
Alternatively, if you are comfortable using the shell, Panix has an install script, see their procmail help page. Visit www.Panix.com.