It could be a problem copying that file (noted in the error) to the network folder. Make sure everyone on the network has the Essential Forms program and the Essential Forms Updater (in the system tray) closed. The efdownloader.exe is probably running somewhere on another machine, which could be found by looking at the task manager in the "Processes" tab on each machine or going to Start>Computer Management and ending the process "Efdownloader.exe" under the "Shared files". Stopping it. Then try the Judicial Council Update again see if it gets past that "Program Stuff files: Efdownloader message at 56-60%. If you are met the same fate. That efdownloader.exe file is running somewhere in the background even though the Essential Forms Updater is not showing in the system tray.
You can open the Essential Forms "Data" folder (under Start>Computer) and check if you see efdownloader flag files which will show-up with efdownloader <Station name>. Go to that station and close out the Essential Forms Updater which is the efdownloader.exe file. It may be running in Task Manager under the Processes tab. After stopping the efdownloader.exe on the machine and the network, try to run the latest Judicial Council Update again.
If you’re still not able to get past the error, it could involve install permissions or antivirus. You could try copying the contents of the update installer to a folder on the hard drive and trying again, or installing in safe mode with networking. Or, if the data folder has already been updated by running the install from another workstation, just copy the program files from the /BIN folder on the installer.