This error can occur if there are older plugins lingering in your plugins folder of Photoshop after installing Suite 8 and trying to launch Photoshop.
To correct the error goto your:
[Local Disk (C:)]\Program Files\Adobe\Adobe Photoshop CSx 64bit\Plugins:
Delete any older plugin files of ours that may still be lingering in the plugins folder or a subfolder in the plugins folder.
Another possibility for the error is if you have Photoshop using an additional Plugins folder. This is a preference set in your Photoshop Preferences>Plugins.
Uncheck the Use Additional Plugins folder, then quit and restart Photoshop.