Doh, why does life have to be so difficult... :-(
Here is what I do after PM5 loads to configure:
1) Preferences -> Launching -> Default application to edit photos:
2) Select: Assign default application:
3) Click on "..." and select path: C:\Program Files\Adobe\Adobe Photoshop CC 2014\Photoshop.exe
4) click on "open"
5) click on "OK"
Now we are back to main PM screen with photos displayed.
6) Select two .rw2 image files.
7) Right click and select "Edit selected photos"
Photoshop CC 2014 will load and come to the foreground and then nothing. It will launch photoshop but does not actually open any images. If you are following this procedure exactly and it still doesn't work for you, would you like me to send you a couple of .rw2 files in case there is something bizarre with how it handles my Panasonic raw files vs your .cr2 files?
Note, this is using Windows 8.1 64bit with Windows 64bit Photoshop CC 2014 (which I believe just comes in 64bit now).
Please let me know the exact set of steps that reproduce the problem, what your Launching settings look like (I assigned PS CC (2014) as a default editor for photos,) and any other details you think may be useful.