I had a satellite receiver do the same thing, 3 of the 4 legs turned into a tar like substance. I got some on my hands and it was really hard to remove.
Used to see it all the time with consumer electronics.
Most cases the tv / video etc etc. hadnt been moved in ages, we would come to collect it and after removing box from top of expensive CRT's would find the rubber feet had eaten into the tv cabinet.
If I remember a manufacturer (rather not say which 1), done a recall cause of this problem, about 7 years ago.
Is right though. Its a chemical reaction between some plastics and rubber.
