Running as administrator masks configuration issues. Some you may have created, some are created by unmaintained software. Elevating privileges is easier than sorting out permissions issues.
I would suggest calling support for the "General Error" problem.
When it comes to relying on old unmaintained software, you are on your own. The registry hacks generally involve altering the permissions in a parts of the registry so the plug-ins can write to them. There is no single solution. It depends on the plug-in. There is a larger problem relying old software. At some point in time, the software may just stop working entirely. The products are already out of support and not maintained.
So for now you must run as administrator and deal with things like the copy probem or disable UAC and deal with the security implications. The media browser should be able to handle the clip copy issue.