I am writing this note as I could not find any description of this problem anywhere. When my new iMac arrived, I purchased Compressor with the hopes of sharing workload distribution with my older iMac. Both are running OS X 10.1.2 and Compressor 4.1.3. After setting up file sharing between the 2 iMacs, I opened Compressor and set up each system to share. From the new iMac, I created a work group that included both systems. When I started to render a video file, the job immediately failed with the following error: Write permissions on /users/shared/library/Application Support. The permissions were set to read/write for user (system) and read-only for group (wheel) and everyone. I ran Disk Utility on both iMacs to Repair Permissions to no avail. I had to open up permissions to read/write for everyone to get past the error. You do this by selecting that Application Support folder with Finder and Get Info (command-I) on it. Unlock the settings with your admin password and pull down the permissions for everyone to read/write. The only folder in this path previously was Adobe (for Air). With permissions changed, now Compressor has a folder for storage where it assembles the piece parts of the video project.