extproc fails with ora 28575

Hello all i am trying to validate procedure using extproc which runs fine on another server/database. however it fails with ora 28575 . Any help on the extproc setup will be appreciated

Oracle SQL*Plus: Release 10.2.0.3.0

AIX 5.3

 listener.ora

LISTENER_EXTPROC =
  (ADDRESS_LIST =
    (ADDRESS = (PROTOCOL = IPC)(KEY = extproc_key))
  )

SID_LIST_LISTENER_EXTPROC =
  (SID_LIST =
    (SID_DESC =
      (SID_NAME = extproc_agent) (ORACLE_HOME = /opt/oracle/product/10.2.0/db)
      (ENVS = "SHLIB_PATH=/opt/oracle/product/10.2.0/db/lib:/lib,EXTPROC_DLLS=/opt/oracle/product/10.2.0/db/lib/libsha.sl")
      (PROGRAM = extproc)
    )
  )

tnsnames.ora

EXTPROC_CONNECTION_DATA=
(DESCRIPTION=
(ADDRESS=(PROTOCOL=ipc)(KEY=extproc_key))
(CONNECT_DATA=