Why can't I download anything from 4shared.com?

[Jules001]

I am a crafter and other crafters share their artwork on this site, but I am currently unable to download anything from that site. I never had a problem before, then suddenly started getting an error session id message, now I don't even get that, all I get is the the green download progress bars in the bottom right hand corner which seem to whizz by and then get the message on the bottom left hand of the screen 'done' but nothing is there? I am running Zonealarm (paid version) which I temporarily disabled to see if this was the problem (it wasn't!) and Avast antivirus. I am also using Firefox as a browser, but if I use GoogleChrome I at least get the 4shared download page, but when I try to download I get a no session id error message. Please help, my sanity is in your hands!