I recently bought a new computer & re-installed photoshop CS5.1 successfully, but can't get the plug ins to work (phototools 2.5 & perfect effects 3, which were a free download with purchase). I am running windows 7 64bit. I copied & pasted them into the plug ins folder (in both applications of photoshop - there is the 32 bit version on 'program files (x86)' & the 64 bit version in 'program files'), but neither will work.
You probably won't get those plugins to work by just copying them.
I'd remove the plugins that you copied and pasted and use the phototools 2.5 & perfect effects 3 plugin installers, as they probably install some other files besides just the plugin itself.