It is a problem while accessing your network share for sure.
Here are some cherry picked error messages from your log:
20:30:34.064 T:3871454000 WARNING: Process directory 'smb://BIGBOX/Mediathèque/SERIE TV/Alphas/' does not exist - skipping scan.
20:30:34.083 T:3871454000 WARNING: Process directory 'smb://BIGBOX/Mediathèque/SERIE TV/Archer/' does not exist - skipping scan.
20:30:34.102 T:3871454000 WARNING: Process directory 'smb://BIGBOX/Mediathèque/SERIE TV/Beyond/' does not exist - skipping scan.
20:37:59.921 T:3512365872 ERROR: GetDirectory - Error getting
20:38:03.754 T:3512365872 ERROR: Previous line repeats 3 times.
20:38:03.755 T:3512365872 ERROR: Read - Error( -14, read call failed with "" )
20:38:03.755 T:3512365872 WARNING: underflow: Error reading file - assuming eof
20:38:04.890 T:3512365872 ERROR: Read - Error( -14, read call failed with "" )
20:38:04.891 T:3512365872 WARNING: underflow: Error reading file - assuming eof
20:38:06.308 T:3716129584 ERROR: Read - Error( -14, read call failed with "" )
20:38:06.308 T:3716129584 WARNING: underflow: Error reading file - assuming eof
20:38:22.567 T:3512365872 ERROR: GetDirectory - Error getting
20:38:22.599 T:4091899920 ERROR: Previous line repeats 3 times.
20:41:17.105 T:4091899920 WARNING: CreateLoader - unsupported protocol(sources) in sources://music.tbn
20:41:37.768 T:3468854064 WARNING: Previous line repeats 2 times.
20:41:37.769 T:3468854064 NOTICE: My Music: Scanning for music info using worker thread, operation took 00:20
20:41:37.829 T:4091899920 WARNING: CreateLoader - unsupported protocol(sources) in sources://music.tbn
20:42:06.442 T:3512365872 ERROR: Open - Unhandled exception
20:42:06.442 T:3512365872 ERROR: Open - Error opening nfs://192.168.1.111/volume1/Mediathèque/MUSIC HQ/Pink Floyd/The Wall/1-01 In the Flesh.flac
20:42:06.442 T:3512365872 ERROR: Init: Error opening file musicdb://recentlyaddedalbums/152/8492.flac?albumid=152
I assume, it has something to do with the special character in your path, because it is broken in your log.
Try to avoid such characters in any path and file names.