I'm surprised folks still want to hold on to their MPEG-2 receivers. All new HD programming is being added in MPEG-4, no? The only advantages the 811 had were their analog OTA tuners (in addition to digital, if you needed analog for some reason) and the UHF remote; that helped me as I had sets in 3 rooms all connected to the 811. But ever since I upgraded the 811 first to a 622 and then finally to an additional 211, I haven't looked back. At the point of the first upgrade I was already missing 5 M-4 channels; at this point it's more like 15 and increasing as more are (slowly!) added. My 811 was also quirky, but I don't remember that specific smart card error. A simple soft boot always reset mine.
To the OP, you can DIY if you feel comfortable changing dishes and LNBs. This time it might pay to let E* do it as part of an upgrade. Even if you own your receiver (I own my 622 and lease the others) you have to pay the monthly access fee in place of a lease fee. There's no economic advantage to owning one that I could ever determine. I upgraded my 811 to the 211 in Aug. when there was a deal to do it. (The $99 upgrade fee was offset by a $10/mo-10-mo. programming credit and in theory there was no commitment.) You might see if E* would be willing to still offer a similar deal, especially as a "customer retention" incentive...