See this thread. The coax from the wall goes into the minibox input, coax out of the minibox must go to the input of the VCR. From the message you are getting sounds like you have the cable direct into the VCR.
I have been unable to play or record to my VCR since installing the mini box also. I have followed the instructions for the connections. I have the cable line from the wall to the mini box, to the VCR, and then to the TV.
I hope someone will respond to our question.
TV works fine with just mini box.
TV works fine with VCR added, (can still watch TV), but I can not play a tape from VCR.