I have just managed to get it to work. I had the problem that JDownloader would have it's usual pop-up to ask for the captcha in my browser, but for some reason it would not work. I have just found out that it was a program, that got installed in my firefox addons. It had been like this for a few days, then I remembered that I had, had Mcafee
web advisor installed, (not by me, probably Mozilla), I have now removed it and everything is OK now.

[Jiaz]

Thanks for the feedback! and informing us about your solution