IMP-00003: ORACLE error %lu encountered

You are trying to import an Oracle export file, but an Oracle error was encountered.
Lookup the "real" Oracle error as indicated in the error message and make corrective actions.
eg:

C:\Temp>imp userid=imp1/imp1 file=expSYSTEM1.dmp fromuser=system touser=imp1

Import: Release 11.2.0.1.0

Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.


Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production

Export file created by EXPORT:V11.02.00 via conventional path

Warning: the objects were exported by SYSTEM, not by you

import done in AL32UTF8 character set and AL16UTF16 NCHAR character set
export client uses WE8MSWIN1252 character set (possible charset conversion)
IMP-00017: following statement failed with ORACLE error 2304:
 "CREATE TYPE "REPCAT$_OBJECT_NULL_VECTOR" TIMESTAMP '2010-04-02:13:20:12' OI"
 "D 'DE89BCC579464D7F8FAE02F2D22CC373'          AS OBJECT"
 "("
 "  -- type owner, name, hashcode for the type represented by null_vector"
 "  type_owner      VARCHAR2(30),"
 "  type_name       VARCHAR2(30),"
 "  type_hashcode   RAW(17),"
 "  -- null_vector for a particular object instance"
 "  -- ROBJ REVISIT: should only contain the null image, and not version#"
 "  null_vector     RAW(2000)"
 ")"
IMP-00003: ORACLE error 2304 encountered
ORA-02304: invalid object identifier literal
IMP-00017: following statement failed with ORACLE error 6550:
 "BEGIN   SYS.DBMS_DEFER_IMPORT_INTERNAL.QUEUE_IMPORT_CHECK('ORA112','IBMPC/W"
 "IN_NT-8.1.0'); END;"
IMP-00003: ORACLE error 6550 encountered
ORA-06550: line 1, column 9:
PLS-00201: identifier 'SYS.DBMS_DEFER_IMPORT_INTERNAL' must be declared
ORA-06550: line 1, column 9:
PL/SQL: Statement ignored
. . importing table                  "DEF$_AQCALL"          0 rows imported
IMP-00017: following statement failed with ORACLE error 6550:
 "BEGIN   SYS.DBMS_DEFER_IMPORT_INTERNAL.QUEUE_IMPORT_CHECK('ORA112','IBMPC/W"
 "IN_NT-8.1.0'); END;"
IMP-00003: ORACLE error 6550 encountered
ORA-06550: line 1, column 9:
PLS-00201: identifier 'SYS.DBMS_DEFER_IMPORT_INTERNAL' must be declared
ORA-06550: line 1, column 9:
PL/SQL: Statement ignored
IMP-00009: abnormal end of export file
Import terminated successfully with warnings.