Server refused to allocate pty

[unix syzadmin]

Hi,

We have Linux server that we use as a trusted host.
So this is the first hop for many unix admins in my company to reach a
target server.

We are getting intermittent errors lately when we try to ssh.  Some times
when we are luck to get an ssh session, we get a different error while we
try to sudo as root.
I guess both of these issues are related.

Any ideas? Please suggest.

*** error when we ssh through putty ***

#Using username "maui".
Authenticating with public key "rsa-key-20080325"
Server refused to allocate pty
tset: standard error: Invalid argument

*** when we get in with luck; still get an error while we try to sudo as
root ***

#more /etc/redhat-release
Red Hat Enterprise Linux AS release 4 (Nahant Update 4)

#sudo su -
Cannot open cloning master pty: No such file or directory
                                                         open pty failed:
Illegal seek

Thanks