Hi Nemix,
If you are porting tracks from Qu to SQ, note that the multitrack folders must contain 18 tracks for Qu, but only 16 for SQ. This catches out a few people.
Also, since you applied sample rate conversion, there is a chance the DAW you used has saved the files in a slightly different format, for example with BWF chunks or a Waves64 header, thus rendering them incompatible with SQ. If using Reaper for example, make sure you are rendering to 96kHz 24bit mono files (24 bit PCM) and untick the Waves64 and BWF options. Finally, make sure all converted files are exactly of the same size.
Hope this helps.