Thank you destinyforever this also worked for me.
Your error message will tell you either the exact line, or the line below, where you should remove the “&”. for me the error said 646, but I had to remove the “&” from 645 (i.e. remove the “& from “&$this”).
After trying to activate again the same error occurred for line 995, so I also removed the “&” from 994 and the plugin activated successfully.
