HI,
I would first try to delete the TD_80 folder. Open a windows explorer window and type %temp% in the URL bar and hit enter, then scroll down and find the TD_80 folder and delete it (don't worry it will be recreated the next time QC/ALM is accessed.

If this doesn't help, then I would suggest getting a copy of the ALM client uninstaller and running it on your local system. When it starts up select the All option and let it run. It will delete all remnants of the client that exist on the system (and it will delete all pre-existing installations of other versions as well as their registry entries and folders.

Then restart the system and reinstall the QC/ALM client. This should resolve your errors and issues.

The error is a very generic error thrown by the system when it is having access issues to the entity trying to be accessed.

I hope this helps.
Dan