Hi, I just checked 1.7.8.4 in 5.2.3f1 and don't see these errors.
I suspect you have duplicate Playmaker dlls in your project. Unity versions 5.0-5.2 have an annoying habit of creating duplicate files that can break your project! Unity 5.3 fixed the issue.
To see if you have duplicate dlls, search your project for PlayMaker 1.dll and PlayMakerEditor 1.dll.
The easiest fix is to find and delete all Playmaker dlls and re-import 1.7.8.4.
BACKUP your project before doing this!!!!
If you find these,