Getting error when assigning value to global variable

 Hello All,

While doing the form personalization,i am assigning a package.function as value to the global variable.It is showing me the error.

The screen shot is attached to this discussion.

I am submitting a request through this function and getting the request id for the program.

The code used as part of the value is as follows

=select xxta_call_sales_conf_package.xxta_call_prog_proc(:ORDER.CREATED_BY,:ORDER.ORDER_NUMBER,'US') from dual.

Thanks in Advance.

Deepak