For pen pressure:
File > Preferences > Tablet
You try to play around with this yet? It should be "Wintab" and "Mouse Mode With Setting Of Tablet Driver(Z)" I think, not sure but just change the options around and see if anything will work.
For Eraser, may be you accidently click the buttons on the pen, down-button will shift you to earse tool by default
Go to File > Modifier Key Setting, Down-Button should be Right Click and Up-Button is Tail Switch. Or you can just change those 2 buttons function in the tablet properties.