ORA-04088: error during execution of trigger ORA-06508: PL/SQL: could not find program unit being called

I have a trigger created in one schema that in used on a table in another schema.

The trigger calls a procedure from a package , this package is defined as current user authid

I get the error when teh trigger reaches the point at which the function call is to be made.

but I dont knwo how to get around that problem... has any got any clues ??

create or replace
TRIGGER TEG.TR_AEC_COMPLETE_TASK_95
 AFTER
  UPDATE
 ON WMIS.wr_task
REFERENCING NEW AS NEW OLD AS OLD
 FOR EACH ROW
WHEN (NEW.wr_task_no = 100 AND
      NEW.task_status_code = 'C' AND
      OLD.task_status_code != 'C')
Declare
....
...
BEgin
..
..
-- follwoing two procs added to trigger
TEG.SPCKG_AEC_MSG_LOG.Application_Log_TEST  -- this call ok

TEG.SPCKG_AEC_BL_TSK_95_CMPLT.RESOLVE_SCHDLNG_PLYGN_5047 -- this is where oracle fails with teh error

..
exception
..
..
end;

this code works fine if i remove teh offending RESOLVE_SCHDLNG_PLYGN_5047 , but i need to add that proc to reslove an issue

this is the error i get

ORA-06508: PL/SQL: could not find program unit being called
ORA-06512: at "TEG.TR_AEC_COMPLETE_TASK_95", line 294
ORA-04088: error during execution of trigger "TEG.TR_AEC_COMPLETE_TASK_95"       

I am thinking is some dort of prvilidges issue .. any clues ...