All downloads are failing

After upgrading to Firefox 33 from Firefox 24 I'm experiencing the following behavour: when I click on a link to download a file the file appears in download list with "Download failed" status. I found a number of similar issues reported, but in my case no file is downloaded (it is not created in the destination folder). If you quickly click on retry icon and then after the "stop" icon appears you click on it, after that clicking on restart icon does the job and the file is actually downloaded, but its size shown in the list is strange (like 9290848902 GB). My OS is Windows 2003 Server R2 SP2, no addons installed. Tried resetting profile, running in Safe Mode and completely reinstalling with no luck. Tried on two different machines with W2K3 - absolutely identical behaviour. I have two types of users - local and domain. Domain users have Application data folder redirection to network drive configured. The problem appears only with domain users, local users (without redirection) are not affected. Also the problem appears only when the file is saved to network location (home folder, my documents folder (redirected to network share)). When saving to local drive - there are no problems.