SQL Plus (Oracle 10G) on Windows 2000

[Guest houghaptea]

We have a server that already has Oracle 9i installed and works fine. When

attempting to install the 10G client on the same box, everything installs

successfully, but when we launch SQL Plus, nothing comes up and a dr watson

occurs. The sql plus for 9i works fine. Also, all other components for 10g

appear to work fine. Can someone tell me if this is a compatibility issue,

or just a configuration issue.

Thanks in advance.