Puzzler (why does this error?)

[inspir]

This line executed in the message box:

put the allowKeyInField of field id 1008 of card id 1002 of stack 
"Untitled 1"

produces this error:

Message execution error:
Error description: Handler: can't find handler

While this line executed in the message box:

put the visible of field id 1008 of card id 1002 of stack "Untitled 1"

simply puts true

Any ideas?

regards,

Geoff Canyon
gcanyon at inspiredlogic.com