Oracle Query Error

Hi
Some help needed in Oracle
I have a table and i m using this query for that and i m getting the following errors

delete from usermaster
where empno=100;

ERROR at line 1:
ORA-01000: maximum open cursors exceeded

or if i do like this..

update usermaster
set username='satya' where empno=100;

ERROR at line 1:
ORA-00604: error occurred at recursive SQL level 1
ORA-01000: maximum open cursors exceeded

What does this mean..
This usermaster table has got no foreign keys under that..
If u have any solution let me know
Bye