[Koha] "Problem sending cart..."

All, We are running Koha 3.0, and everything pretty much works like it should. One issue we are having, though, is that users cannot email in their shopping carts. We get an error messaging saying "Problem sending cart..." I don't see anything in the system preferences that relates to the cart, and the only place where it asks for an email address is filled in. Any thoughts as to how to fix the problem? Thanks Chris Morrison Bertha Smith Library Luther Rice Seminary and University Lithonia, GA 30038