This is the workflow that really works around the issue:
First, install MP-TVSeries v4.5.1.745, download.
Second, check TV-Series configuration and delete all faulty series from database (imported...
I also had a crash. It was solved when I installed the (then) newest version 6.0.7.454. Maybe it's a version thing. Try roll back to this version. I have MP 1.36 (x86), Trakt 6.0.7.454 and skin...
Trakt overhauled its website / service shortly. Since then, I could no longer authenticate to Trakt from Mediaportal. It is not SSL, I got this checked.