I had the same problem. The solution is easy: you need to copy the entire content of the C:\Program Files\Adobe\Adobe Photoshop CC\Plug-ins folder to C:\Program Files\Adobe\Adobe Photoshop CC 2014\Plug-ins.
I found the solution in the blog of Glyn Dewis see here: http://glyndewis.com/
Filter Forge 4 and all of Flaming Pear's library of plugins. Its not necessarily the volume, but the re-inputting all the serial numbers again.
I assume that solution would work with a Mac?
EDIT: Actually, i just had a look at his blog, and his instructions are for a Mac. I'll give it a go.
EDIT 2: Well they appear in PS CC (2014), but I still have to re-register them with their serial numbers. Which is going to take an age.