" I talked to them to be sure SMTP was enabled"
SMTP being enabled is not the same as having the mail objects installed.
The most common mail object is CDOSYS, but when installing the IIS server, it needs to be selected as an add on object, it is not part of the default IIS set up.
The SMTP server is another install altogether.
THE CDOSYS object is the method that the IIS Server will use to communicate with the SMTP server.
Another way to look at it is the Access Database versus the IIS server.
In the IIS Server, you need to also install MDAC (Microsoft Data Access Components)
This includdes the Microsoft.Jet.OLEDB.4.0 driver that allows the IIS server to talk to the Database.
this is the same as the CDOSYS drivers. The CDOSYS driver allows the IIS server to talk to the SMTP server.