Kai-Mikael Jää-Aro ,
Try the Perian Component. it might play your DX50.
http://perian.org/#download
Please consider removing obsolete QuickTime Components: FFusion, Xvid Delegate, 3ivX, DivX, XviD, msmpeg4v1, msmpeg4v2, AviImporter, EX_M4S2, and Casio AVI Importer...From Perian Support.
Worth a shot and Perian is favorite in this forum for playing back DivX files.