custom property woes

[Björnke von Gierke]

I do not understand this. WHen I refer to a custom property it 
generates an error! for example typing this in the message box:

put the players of this stack

returns:

Script compile error:
Error description: Expression: bad factor

even if the property did not exist it should return just empty but 
never generate an error??
also a similar line in the code of my stack which looks like this:

send "startTurn" to stack (Line 2 of the Players of me)

returns this error when I click apply:

      	compiling at 12:02:57 AM
Type	Expression: bad factor
Object	Untitled 1
Line	send "startTurn" to stack (Line 2 of the Players of me)
Hint	

what the hell is going on?
Mac OS X 10.2.6 rev version 2.0rc2