This is a common problem. Moving def$_aqcall table to another tablespace should be fine.

You may want to take a look at the following steps:

Moving the SYSTEM catalog tables in Oracle8:
============================================

1. Take a backup of the site where the SYSTEM catalog tables are
going to be moved.

2. Make sure deftran, defcall, deferror and dba_repcatlog on the
site where the tables are going to be moved to are empty.

3. Connect to Sql*Plus as REPADMIN and issue for EACH repgroup:

SQL> EXECUTE DBMS_REPCAT.SUSPEND_MASTER_ACTIVITY('GNAME');

4. Export user SYSTEM.

$ exp system/manager file=move.dmp

5. Connect to Sql*Plus as SYSTEM. Drop the following tables in
the order specified below:

drop table SYSTEM.DEF$_CALLDEST;
drop table SYSTEM.DEF$_DEFAULTDEST;
drop table SYSTEM.DEF$_ERROR;
drop table SYSTEM.DEF$_ORIGIN;
drop table SYSTEM.REPCAT$_REPSCHEMA;
drop table SYSTEM.DEF$_DESTINATION ;

6. Connect to Sql*Plus as REPADMIN and issue:

SQL> EXECUTE DBMS_AQADM.DROP_QUEUE_TABLE('SYSTEM.DEF$_AQCALL',TRUE);

SQL> EXECUTE DBMS_AQADM.DROP_QUEUE_TABLE('SYSTEM.DEF$_AQERROR',TRUE);

7. Connect to Sql*Plus as SYS and issue:

SQL> ALTER USER SYSTEM DEFAULT TABLESPACE
QUOTA UNLIMITED ON ;

SQL> ALTER USER SYSTEM QUOTA 0 ON SYSTEM;

SQL> REVOKE UNLIMITED TABLESPACE FROM SYSTEM;

8. Connect to Sql*Plus as SYSTEM and run the script "catdefrt.sql"
located in the "$ORACLE_HOME/rdbms/admin" directory.

Note: The errors on some CREATE TABLE statements and CREATE
INDEXES of mature tables or indexes indicating they
already exist can be safely ignored.

9. Import the tables in the order listed from your export file
from step 4 above.

SYSTEM.DEF$_DESTINATION
SYSTEM.DEF$_CALLDEST
SYSTEM.DEF$_DEFAULTDEST
SYSTEM.DEF$_ERROR
SYSTEM.DEF$_ORIGIN
SYSTEM.REPCAT$_REPSCHEMA

Example:

$ imp
Username: system
Password:

Connected to: Oracle8 Enterprise Edition Release 8.0.3.0.0
- Production
With the Partitioning and Objects options
PL/SQL Release 8.0.3.0.0 - Production

Import file: expdat.dmp > move.dmp


Enter insert buffer size (minimum is 4096) 30720>

Export file created by EXPORT:V08.00.03 via conventional path
List contents of import file only (yes/no): no >

Ignore create error due to object existence (yes/no): no >

Import grants (yes/no): yes >

Import table data (yes/no): yes >

Import entire export file (yes/no): no >
Username: system

Enter table(T) or partition(T:P) names. Null list means all tables for user
Enter table(T) or partition(T:P) name or . if done: def$_destination

Enter table(T) or partition(T:P) name or . if done: def$_calldest

Enter table(T) or partition(T:P) name or . if done: def$_defaultdest

Enter table(T) or partition(T:P) name or . if done: def$_error

Enter table(T) or partition(T:P) name or . if done: def$_origin

Enter table(T) or partition(T:P) name or . if done: repcat$_repschema

Enter table(T) or partition(T:P) name or . if done: .


. importing SYSTEM's objects into SYSTEM
. . importing table "DEF$_CALLDEST" 0 rows imported
. . importing table "DEF$_DEFAULTDEST" 0 rows imported
. . importing table "DEF$_DESTINATION" 2 rows imported
. . importing table "DEF$_ERROR" 0 rows imported
. . importing table "DEF$_ORIGIN" 0 rows imported
. . importing table "REPCAT$_REPSCHEMA" 6 rows imported
About to enable constraints...
Import terminated successfully with warnings.

10. Connect as user SYS and issue:

SQL> GRANT UNLIMITED TABLESPACE TO SYSTEM;
.