Could you provide some more details about what you would like to accomplish?
Ideally, I would like the transaction monitor to abort and create an incident. At the very least, I would like an incident generated if the execution takes longer than 60 seconds.
You have to add a condicion "Response Time < 60 sec" Then, you can create a rule with that condicion to rise an incident when the expression is false.
Perhaps you could spread some GetTime or GetTimeStamp calls throughout your script and if the elapsed time is too great then call RaiseError and "return 0".