Export problem (during .exporting posttable actions)

everything was doing fine until the following step.... Anybody has any idea?

Thanx

. exporting posttables actions
EXP-00008: ORACLE error 4045 encountered ORA-04045: errors during recompilation/revalidation of SYS.DBMS_AQ_IMPORT_INTERN
AL

ORA-06552: PL/SQL: Compilation unit analysis terminated
ORA-06553: PLS-905: object SYS.AQ$_SUBSCRIBERS is invalid
ORA-06508: PL/SQL: could not find program unit being called
ORA-06512: at line 1
ORA-06512: at "SYS.DBMS_SYS_SQL", line 787
ORA-06512: at "SYS.DBMS_SQL", line 328
ORA-06512: at "SYS.DBMS_EXPORT_EXTENSION", line 82
ORA-06512: at "SYS.DBMS_EXPORT_EXTENSION", line 133
ORA-06512: at line 1
EXP-00000: Export terminated unsuccessfully