[CentOS] can not login to server (use ssh)

we have CENTOS 5.6 on DELL server.  I tried to use ssh login to server and failed:

ssh oracle at ora10
oracle at ora10's password: 
Read from remote host ora10: Connection reset by peer
Connection to ora10 closed.

I have not problem login as "root" or other users.

Is it possible too many processes run by "oracle" and don't allow me login.

I check server current have 2000 oracle processes running.

$ ps -ef|grep oracle|wc -l
2000

anyone know how to fix this issue?

Thanks.