I have used the QuickTest Print Log for trouble shooting. This displays information in the QuickTest Print Log window during the run session. The QuickTest Print Log window remains open while the run session continues, until you close it.

The QuickTest Print Log is stored at %Temp$QTPrintLog.txt and you can use it to find location of errors.

I have created a function library for debugging which does help out.

Function   myDebug(myMsg)
	If debugMode then
		print now &''  '' &  myMsg
	End if
End Function

debugMode=false
' line of code
'line of code
myDebug('' test  line 2'')
'line of code
zVar=12 
myDebug ( '' zVar= '' & zVar)