[Exim] exim + squirrelmail

Hello , I am having some trouble with configuring exim and squirrellmail
to work together.

I have my squirrelmail configured to use SMTP, instead of Sendmail...
When I try to send an email from squirrelmail I get an error similar to
this...

*ERROR:* Syntax error in parameters or arguments
Server replied: 501 <tanderso@>: domain missing or malformed

Now, when I send mail via a normal email application mail sends/receives
fine... do you think this is a problem related more to squirrelmail, or
something in my exim config?

Anyone else had similar problems?

thanks!
-travis