The key to change is:

 HKEY_LOCAL_MACHINE\SOFTWARE\Computer Associates

Right click and go to permissions. Give full control to everyone for this key.

Full control for everyone will work if and only if you are using a windows XP machine. Everyone that I have talked to that doesn't have a windows XP machine is not able to set permissions on a key by key basis.

To edit registry key permissions on other versions of Windows, you must use reged32.exe instead of regedit.exe.

Also this trick alone will not work because general users do not have access to install the certificate that is required the first time Opal logs into the Case system. So here are the steps I used:

1. install the client as an administrator.
2. also as an administrator visit the Case solar website once and load solar all the way until you get the to login screen (note it is not necessary to actually log in). You will at some point be asked to install a "client" to make Opal work, this is actually a certificate and it requires administrative privileges to install.
3. Do the registry update described above.
4. Log in as a generic user to test to see if Opal can load. If you can get all the way to the login screen without an error message you should be okay.