SQL & PL/SQL

HELLO
I HAVE ORACLE11G RELEASE 2 64BIT AND PLATFORME LINUX REDHAT AS 5 64bit
when in like execute a programm plsql i have his error ORA-28575


in a listener.ora file in have :
LISTENER =
(ADRESS_LIST
(ADRESS =(PROTOCOL=IPC) (KEY=EXTPROC))
)

SID_LIST_LISTENER =(SID_LIST
(SID_DESC=(SID_NAME=xx11g)
(ORACLE_HOME = /u01/app/oracle/product/11.2.0/dbhome))
(SID_DESC=(SID_NAME=extproc)
(ORACLE_HOME = /u01/app/oracle/product/11.2.0/dbhome)
(PROGRAME=extproc))
)

and tnsnames.ora i have:
LISTENER_PADSS11G =
(ADDRESS = (PROTOCOL = TCP)(HOST = x.x.x.x)(PORT = 1526))


PADSS11G =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = x.x.x.x)(PORT = 1526))
(ADDRESS = (PROTOCOL = IPC)(Key = EXTPROC))
)
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = xx11g)
)
)

EXTPROC_CONNECTION_DATA =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = IPC)(Key = EXTPROC))
)
(CONNECT_DATA =
(SID = extproc)
)
)


thank y