If you use the search facility of this web site and search for "all cards busy", you will find numerous threads relating to this problem (so there is probably more than one cause).
Your symptoms (one tuner working, others not working for simultaneous use) suggest that you have setup only one tuner (so TV Server can use only one...
If you use the search facility of this web site and search for "all cards busy", you will find numerous threads relating to this...
I have two video cards both capable of recording two tv channels
However if I try to record a program and watch another station...