Two HR's, Two Problems

HR20-100, Loses all MPEG 4 HD channels. Have had to reset anywhere from daily to once or twice weekly when both tuners are used. Had this problem for several months. Moved receiver to bedroom where there is only one sat cable, and one tuner being used. Haven't had this problem since. I have called tech support numerous times about this problem after being told to call back while the problem is ongoing. The only solution they have is to reset the receiver (imagine that).
A reset usually corrects it until a day or two later when it happens again. Each time I call I'm told that they will note this problem on my account and if it continues they may have to send out a technician. However when it happens again they can't seem to find anything noted on my account about this problem
As I said earlier I haven't had this problem since I moved the receiver to another room with only one tuner in use.

HR21-100, Have had this receiver about a month. When it powers up I get a message stating something to the effect of "cannot read access card" A reset will usually correct this also. Have had to reset from multiple times daily to two or three times weekly, however it has not done this in about a week. Also I thought my HR20 was slow but this receiver is painfully slow, when using the guide or menu.

Both receivers are running the latest national software release.