How are you trying to read the ATRs off of the AVG Cart?  Are you using a SIO cable from the cartridge to SIO port or just reading off the AVG Cart itself?  I ask because, even though I don't own an AVG, I have tried to copy ATRs from a UNO Cart to disk and only met with limited success.     Also, can you post the "Zork" ATR that you are using?  I can see if I have any success in copying it to floppy using another method.