1. This is a rare error that can usually be fixed by re-installing Legacy from the Web. There is no need to uninstall the program.
LEGACY: Click Here
Previous version of Legacy: Click Here and download the final release (build) of your version.
2. Make certain that any spyware scanners or antivirus programs are temporarily disabled. It's important that if a spyware scanner wants to remove a file like ActBar.ocx that you do not allow it to do so, or the problem will just keep repeating.
If these steps fix the problem, you can stop here.
3. If the above steps do not fix the problem, then uninstall Legacy and then reinstall it.