Network Solutions Certificate won"t install to SBS2003

I created a certificate request in IIS for SBS2003 and sent it to Network
Solutions.
When I try to install it it gives me an error that the pending cert. cannot
be installed.?? My internal domain is XXX.XXXX.local on the inside. and
mail.XXXX.xom is what I used to generae the cert as a common name.