Reply to Heat problems with vci-300

This weekend I played off my friend's VCI-300 for two events. The first was outside and the VCI performed terribly. After about 3 songs it only started outputting clicks when I spun the platters, I reset it and upped the latency and had similar problems a couple songs later. I covered it up and played off my other laptop, onboard sound, no mixing. (lame)
That afternoon at a different venue, which was indoors, the VCI played well for a while, but towards the end of the evening it started crackling on the line-in and the mic. It got progressively worse, even when we changed mics. When we were done with the evening, we couldn't use the mic or line-in, it was all garbled. (There NEEDS to be a bigger mic volume knob btw.)
After believeing about it, could both issues be a heat problem? It was very hot outside, and inside it was on a tablecloth which may have blocked air circulation. Are these things really that sensitive to heat where they will quit playing? Maybe there should be some kind of fan inside? Anybody have other theories?