Can't reply in gmaili with firefox

I'm not sure if this is a mac problem. a firefox problem or a gmail problem.
I cannot replay to e-mails in gmail and I can't save drafts. If I tab down to the reply box I can select the entire box but when I hit a key my mouse arrow disappears. I can type in the address box and the subject box. I can stil use safari to reply to e-mails. Also. If I open a draft to reply it is empty (no writing saved) all other text boxes work fine and I have tried reloading firefox onto my powerbook. (about a year old) any advice?