Where is FOLDERS32?
Is it in under <root drive>\Program Files\ ?
Does it work if it is <root drive\Program Files (x86)\ ?
I know the registry does some odd things regarding a 32 bit app vs a 64 bit app. Maybe those folders have special odd things as well. Just a guess.
The WoW64 subsystem redirects shortcuts that point to the 64-bit Program Files to the 32-bit Program Files (x86) causing the plugin to not be found.
The simplest fix would be to copy the 32-bit plugin into the Plug-Ins folder of the 32-bit version of Photoshop.
Unfortunately Wow64DisableWow64FsRedirection does not work for %PROGRAMFILES%, so a 32-bit application would have to attempt to fix the path manually.