You ABSOLUTELY do not want to identify the plug-ins folder from an older version of Photoshop as your Extra Plug-ins Folder. There are plug-ins provided with the older version of Photoshop that are incompatible with any other version.
You will need to reinstall your plug-ins, or copy just those that you can't reinstall. And keep in mind that not every plug-in is stand-alone - many of them put library files, etc. in the Photoshop main folder.
Are any of the plug-ins that you copied those that are supplied with Photoshop CS5?
If not, then the 3rd party plug-ins you're trying to access likely need library files that were installed into the Photoshop CS5 main program folder. You may be able to isolate them by looking for dates that are similar to the plug-in file that you did copy.
>> It began when the CS5 folder was identified as an alternative location to search for plug ins.
Big mistake. Go turn that preference off.
>> All the plugins are compatable with CS5. Did not reinstall but copied the CS5 64 bit plug in file to the CS6 64 bit Plugin directory.
Go delete everything out of the CS6 plugins directory.
Then see if you can reinstall your third party plugins for CS6.
But you should never, ever try to load the Adobe plugins from an older version of Photoshop like that -- many of them will cause conflicts or duplicated items in the menus. Some will just cause crashes because they are only intended to work with the version of Photoshop that they shipped with.