This error occurs sometimes :
When I try to execute the following PL-SQL code I have right results:
PLS-00707: unsupported construct or internal error [2603]
It seems to be caused by the parameter PL/SCOPE variable when it uses the value “IDENTIFIERS:ALL”.
SQL Developer during connection establishing changes the session parameter PLSCOPE_SETTINGS from IDENTIFIERS:NONE (default) to IDENTIFIERS:ALL.
Same error was received in SQL PLUS when issuing an “alter session set PLSCOPE_SETTINGS=IDENTIFIERS:ALL”.
More about PL/Scope can be found here:
http://docs.oracle.com/cd/B28359_01/appdev.111/b28424/adfns_plscope.htm
http://docs.oracle.com/cd/B28359_01/server.111/b28320/initparams178.htm