Some notes from forums :
1. First make sure your SharePoint server is on the latest patch level. After that, download the ProcMon from SysInternals, set the correct filters in order to avoid the deluge of information, and find out if you have an access denied exception on the Windows temp folder.
2. Check if you have enough Disk Space available for your Database or not? Clear unwanted files and free some solid (atleast 10GB) disk space.
3. Someone said - I found the error. It was an issue with the web.config file. There were some parameters that needed to be changed for the trust level and session variables.