Modem port already open???

I am working on a Dell Latitude D 600 laptop for a
customer. This system has built in Lan, Modem and
Wireless internet capabilities.

When I try to dial out using their any dial up account, I
get the following error message;
"Error 633: the modem (or other conecting device) is
aready in use or is not comfigured correctly"

I have disabled all other networking devices and still
get the same message.

When I go to modem properties and try to do a diagnostic
I get an error message that says the port is already
opened or in use by another device.

ANY ideas how I can resolve this issue??

Thanks in advance,

Dwight
PS: Please email any ideas to my email address above
thank you!
..