[Exim] Squirrel Mail

I have a domain and site setup and running on it's original hosting
(server a) provider but I moved all the email accounts to my server
(server b) i just got setup with Ensim and pointed the MX records to
the server b but I can't check any emails through webmail because when
I click on "Read Email" the url goes to http://MY-SITE/squirrelmail/
which doesn't exist. If I go to http://MY-IP/~MY-SITE/squirrelmail/
then I get a page not found error.

So does anyone know how to check emails for sites that don't have the
www pointed to the server but only the MX and mail records pointed to
it?

Thanks
- Richard S.