IE 5.5 Search Button crashes NT4.0

When users, behind a firewall, click on the Search button the search window appears on the left. At the botton of that window it says ‘loading search settings.’ Eventually the systems virtual memory is expended and the NT4.0 blue screans. This does not happen on machines outside the firewall. Could this be a Firewall issue or is it a problem in IE5.5 that can be fixed? Recreating users profile helps as long as the user doen’t use the search button. We’ve had to reload seven hard drives inthe past two weeks because the system did not recover.