Oracle Database Discussions

we have got a TEST database where data is not so important. now there is a requirement to drop a tablespace but it has got referenced tables
in another tablespaces.. inspite of giving CASCADE CONSTRAINTS its not working. following error is thrown..

SQL> drop tablespace INTER_TS including contents and datafiles cascade constraints;
drop tablespace INTER_TS including contents and datafiles cascade constraints
*
ERROR at line 1:
ORA-00604: error occurred at recursive SQL level 1
ORA-02429: cannot drop index used for enforcement of unique/primary key


please help... my requirement is anyhow i've to delete the tablespace INTER_TS.

regards