What is your exact username on your PC? The username is used by the IDE to provide the location used to install part support information extracted from the SDK. From the errors you are seeing we suspect your issues is related to "an unusual character", maybe an "&", in your username.
In which case, the only workaround we can think of for the moment is to use the IDE under an alternative username.
I apologise for the inconvenience and we will look into solving this issue in a future release.
Regards,
MCUXpresso IDE Support