I use firefox all the time and i never have that kind of problem
But, what i would suggest that you do is uninstall and then reinstall directly from the website. If that doesnt work, ask Customer Service
Or you could use IE or Safari? i use all three of those -_-;
I know! Firefox does that to me alllllll the time when I'm typing emails like I'll be typing "and the fox went for a walk in the green woods." and it ends up "and twenthe for a walk in the fogreen woodsx." it makes me so angry!
and also KAWAIIIIII I want the Bo peach one, they're so cute~!