Recording

When I try to record my synth thats plugged into my audio interface in renoise, the only option renoise gives me is MASTER IN for many lines, although it doesnt recognize sound is being inputted externally. Does anyone know what might be the problem? It worked fine with renoise on my other computer.

Are your line-in devices in the driver enabled? (not muted)
What in-device has been selected in the Renoise Audio preferences?
Does your system has more than one soundcard? (one you bought separately and usually one embedded on the mainboard)