Hello.

I've got SoundBlaster AWE64 and ROland PC-180A. I'm trying to connect it
to my PC but with no results. I think that the problem is in the cable
between ROland and soundcard. I heard that it is a common problem, but I
don't know how to resolve it. Where can I get a "proper" cable or how can
I test it?

One way to do a test is connect a midi keyboard by a midi cable directly to the
sound module, or keyboard you want to test.

You will know real quick if the midi cable is ok or not., but you do need to
transmit on the right channel that the module is set to at.

Midi cables are not that often the culprit. 

More likely you did not set the ports to use, the channels, set this also in
your tracks, or in versions of cakewalk, set the mapping of channels to ports.

There are quite a few things to set, and usually new persons to midi, forget
one of them.