strange PRAGMA RESTRICT_REFERENCES Violation

Below is a simple function that returns first 6 digits of phone# No problem compiling...when nothing is called in Body's exec. section....

But when I call a procedure in Body's exec. section I get PLS-00452...Oracle complains about the function violating its pragma....
(That procedure has nothing to do with the pragma function) What gives ????
Thanks

Rob
8.1.7.2/AIX

• Declared in Pkg Spec FUNCTION area_code_exchange (phone_in IN customer.phone%TYPE) RETURN NUMBER; PRAGMA RESTRICT_REFERENCES (area_code_exchange, WNDS);
• In Body FUNCTION area_code_exchange (phone_in IN customer.phone%TYPE) RETURN NUMBER IS BEGIN RETURN nvl(to_number(substr(phone_in,1,6)), 0); END;