I seem to be having the same issue here and it's really quite infuriating. Adding to the frustration that the usual freezing would bring is that fact that it doesn't do it consistently. Sometimes the game is perfectly playable; each area comes up almost instantly and the game runs smoothly. But then, sometimes it gets stuck. This seems to have a chilling effect for me. Rather than freely exploring the areas I try to find a solution in my current room in hopes that I don't have to go somewhere else and have the game lock up.
I have stumbled upon a rather obnoxious solution, however, if I minimize the game using Alt+Enter and then bring it back up it I seem to overcome the freeze.
Of course, that's a tremendously obnoxious solution and certainly disrupts any sort of immersion the game would normally allow.
Sigh.
Thankfully this hasn't been a problem with Tales of Monkey Island... and I don't think it's an issue in Strong Bad either.
But... you know, I want to play Sam and Max