I have no problems at all with enabling the interrupt (just tried it).
Probably you have made a typo or forgot the "()".
intr is an output signal which -as you already did- should be connected to an isr-usermodule.
Have a look into the "System Reference Guide" (can be reached via "Help") to get a look at how to declare and define an interrupt handler.
Lastly start your handler with "isr_StartEx(Handler);"
When your problem still remains, post complete project here. Use "Create Workspace Bundle" from within Creator.
Calling the interrupt pin an input under the "parameters" section is a mistake - it is an output. Look at the rest of the datasheet.
The interrupt will be generated when a pin (as defined in the interrupt mask) changes.
I just tested the interrupt generation, and did not get this warning (using Creator 2.2 SP1)