Hello,
This may not have anything to do with you problem, but I performed a fresh installation of osTicket and faced exactly the same symptoms: clicking on the Admin Panel link just led to a blank page. After enabling error reporting, the same errors were reported.
I decided to delete everything from my server (osTicket folders and database) and restart everything from scratch. When I started reuploading all the files, I noticed that my FTP client had the "convert filenames to lowercase" option turned on: I turned it OFF started uploading the files to my linux server.
This is the only thing I had to do to get a fully functional osTicket on my server: you might want to check if your FTP client does not have such an option mistakenly turned ON. This did the trick for me.
Phil.
