FTP Installation Problem

OK, so I was using the plugin browser and after I select a plugin and go to to enter my ftp information and my information is already filled in incorrectly. I try to correct it but when i click install it gives me an error message and in the fields is the incorrect information again. I’ve already cleared my browser’s cookies and cache, btw I’m using Firefox 3. So if you can help me please do.

Much Appreciated,
Kevin