Yes, I did posted the same problem last year, and it was not solved. As such, I did a new posting, hoping someone knows how. I did as you said, download the latest version of greensock, cleaned the project, re-import and path it and all...but it did not work. Only when I manually deleted any residues from the bin-debug folder and the bin-release-temp folder, export a new release build, and IT WORKS!
So it might be just like you said Carl. The greensock versions in the bin-release-temp folder and the bin-debug folder might had been conflicting with the latest greensock I put in my lib folder. Overall, thanks a lot. Apologies if I wasted your time.