Check to see if you have Reader installed also and uninstall if so. Also, if any of these machines PREVIOUSLY had reader installed, then you need to clean up the old installations. Esp the DLL assocaited with the web plug-in. See below article. If after removing all references to Reader doesn't work, then reboot and do a Repair on Acrobat. If that doesn't work, then uninstall/reinstall Acrobat. That worked for me.
I finally found a solution to this problem and I can now access pdf forms in LiveCycle Workspace - YES
I followed this guide to an solution:
I found out that my registry "HKEY_CURRENT_USER\Software\Adobe" was 2734 KB!! on my normal user that got the error in Workspace.
I have an admin user and when I exported the same registry key it was only 75 Kb. My admin user did not have the error in workspace.
The registry "HKEY_CURRENT_USER\Software\Adobe" for my normal user account was holding all kind of outdated settings from my 9 years in the company. I deleted all keys for products and versions no longer installed/used.
*Remember backup before you start deleting*
I then saved and restarted the PC. I logged in to my normal user account. I then open workspace and was able to open a pdf form
I hope this solution can help a lot of people outthere. I spend almost a full day to find a solution so happy to share