hi i am Rob i might be able to help you.
what is the exact error message when you try to save the documents ?
you are either trying to save to a folder that you no longer have saving rights in. or it may be that this version of word perfect is just not compatible with windows 10 and you would need to upgrade. But i can check all possible ways to make it work if it is possible to get it running. windows 10 is very new and they havent got a complete list of what works and what wont yet.
wp 12 is compatible with windows 8 so i would think it should work with win 10
it might need to be reinstalled or you can try the repair button in the control panel under programs
can you try that and get back to me as to whether it worked a full uninstall and reinstall would probably be better but the repair is faster and easier