Unidentified subject!

        Hello there...
        
        I'm just configuring sendmail 8.6.12 but I have problems
with procmail users. The error is:

/home/nas/.forward: line 1: forwarding to "|IFS=' '; exec 
/usr/local/bin/procmail #nas"
/home/nas/.forward: line 1: "|IFS=' '; exec /usr/local/bin/procmail #nas"... 
User nas(_at_)usb(_dot_)ve doesn't have a valid shell for mailing to programs

        Your help will be apreciated....

        Thanx in advance

        timoto(_at_)usb(_dot_)ve