I do not have WMP 11,but this is what i found.
Open IE>TOOLS>internet optionsa>connections(tab)>click lan settings>take a look at your proxy settings.
Change back to "Automatically detect settings" reboot.
Tom
I recently installed the beta of Windows Media Player 11. Now, when I run it and Firefox at the same time, Firefox often crashes. It seems to disappear, and I try to reopen it, but receive a message saying that Firefox is already running. The only way to restart Firefox then is to do Ctrl-Alt-Del and end the process, and then click on Firefox. Any solutions besides uninstalling WMP 11?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic