Firefox 4/5: java.io.IOException

So, we’ve had / have a really annoying inconsistent error when using Firefox 4 (and now duplicated in FF 5).

Scenario:
User logs into Rhythmyx Content Explorer. Java Applet loads (shows 100%). Java Applet crashes and the user is just left with the banner (and tabs) and a white screen where the applet should have displayed content.

Errors thrown in the Java Console log:
java.io.IOException: Pipe is already shut down and
java.io.IOException: Error 233 writing to named pipe

Trying to solve the problem:
[ul]
[li]The problem, once manifested is reproducible over and over (despite clearing java cache, browser cache, class cache, restarting the browser)[/li][li]The User can log in with other browsers (IE, Chrome) and the applet will load.[/li][li] A different user can log in with FF (in the same open firefox window…after the first one has crashed) and not experience the same problem.[/li][/ul].

A Whaaaa!!! Solution:
It appears that after the java has crashed, if the user switches communities, then the other community will load without Java crashing. The user is can then switch back to the original community. Furthermore, after restarting the browser, the problem appears to have disappeared (they can log in just fine to the original community).

So… has anyone else experienced this fine…feature? (And know why it is doing what it is doing? And also why switching communities is a solution?)