It sounds like the Web Client did not auto-load (a common problem with NFuse and Netscape). To be sure, go to you add/remove programs and verify whether you have an ICA Web Client entry. If so, with IE, things like emptying the temporary IE cache and ensure that the browser is not set to save encrypted files to disk can create issues. Perhaps the same types of actions and settings affect Netscape. I have not run into any of those, but who knows.