I quickly checked and I was able to log in from firefox. There was no problem and captcha worked. You may want to check if the javascript is the latest version and indeed activated.
before I posted here I spent 30 minutes googling and trying everything you suggested.
to not avail - but firefox IS getting worse with each new version, time for a change anyways. I have had trouble with that shitty software since about a year on a regular basis.
thanx for your assistance
-sam