We do not experience any problem with QuickTime 7.4.5, so this could have been a temporary glitch. Nevertheless, it's a good idea to stick with the QuickTime that was shipped with ArchiCAD, as that was thoroughly tested with ArchiCAD.
I know it's hard
not
to update these days, especially if you use iTunes. Thanks for the report anyway.
Gergely Kmethy
VP, Customer Success, Graphisoft