I think there may be a problem with the Student version installer.
For now, try manually importing the package in Playmaker/Editor/Install while I investigate...
So do you unarchive the .unitypackage straight into that folder?
Edit: I found the location in the individual project folder. I extracted the .unitypackage file and the install did get further this time.
I got this error on 234 files "A meta data file (.meta) exists but its asset 'Assets/PlayMaker/Editor/Install/002c89f108a697847977b73c3bbe823e/asset' can't be found. When moving or deleting files outside of Unity, please ensure that the corresponding .meta file is moved or deleted along with it."
and then again the "Failed to import package with error: Couldn't decompress package
UnityEditor.AssetDatabase:ImportPackage(String, Boolean)" error