I am having the same problem, I use dapper drake though but I think this is the problem of firefox itself. I tried to install kantipurfont but it didn't help. If someone had solved this problem in firefox that may be helpful for ubuntu. I am not using windows anymore and there are lots of things I have to fix in ubuntu. I also have problem using WINE the application gets installed but cannot use them for some reason. I think ithis is the price to pay for living freely. But I like it in many otherways. Keep this ubuntu thread alive.