ORA-00020 Maximum Number Of Processes

select * from v$version;

BANNER
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Oracle Database 11g Enterprise Edition Release 11.2.0.2.0 - 64bit Production
PL/SQL Release 11.2.0.2.0 - Production
CORE    11.2.0.2.0      Production
TNS for IBM/AIX RISC System/6000: Version 11.2.0.2.0 - Production
NLSRTL Version 11.2.0.2.0 - ProductionI got below error on the datases.

ORA-00020: maximum number of processesBased on the suggestion got from previous posts, I did kill some (LOCAL=NO) processes to get myself in. When I looked at the number of processes the number is 150, I changed it to 1000. After a day I got the same error.

ORA-00020: maximum number of processes (1000) exceededI killed processes again to let my self in, bases on the post below, I queried database

ORA-00020: maximum number of processes (%s) exceededHere is the query to find out if there are any processes with out session attached to it.

select spid from v$process where addr not in (select paddr from v$session);Result

SPID
null
35259840
36897866
13369762

[Code]...

To determine the from where greatest number of processes originated

SELECT MACHINE, COUNT(*) FROM V$SESSION GROUP BY MACHINE;Machine     Count(*)
     2
CAPITAL-D3F0092     1
DQAKDCDKLCSW01     14
desmond     20
DQAKDCDKLCSA01     52

My question is why I am keep getting this? Why do increasing process from 150 to 1000 did not resolve the issue?

What can I do to make sure that I don't get this error again?