I'm using the DVD Profiler App since 2013 and ran it without any problem on two smartphones and two android-based media-players in that time.

Until ~a week ago when suddenly the app wouldn't start on my recent phone and at the same time two other apps that were installed on the SD card also quit working.

So I tried the usual, deleted the DB tried to sync again, de-installed app and re-installed, all to no avail. Sometime a part of the profile were copied, one time even all but the covers wouldn't sync at all.
At one time the android app manager even told me that the Profiler app had 256GB data ... impressive on a phone with 2GB internal memory and a 16GB SD card. 

As I suspected the SD card from the beginning, because of the other malfunctioning apps, I bit the bullet and bought a new one, moved all apps back to internal, unmounted the old SD card via memory manager (or however it is called on English) and put the new one in.

And what do you know, installed DVD Profiler again, sync and 30min later everything was right as rain. 

So a buggy SD card is always something you should look out for if the syncing won't work.