Webplayer hangs on loading scene

The first scene in my game loads fine every time but sometimes the second scene (the level select) hangs and never completes loading. It also sometimes causes the browser to exit or crash. I’ve tried loading different scenes but the problem remains - the first scene loads, the next scene sometimes hangs. What’s causing this? You can try it yourself here:

Surveillant - Web version

I get this in my log when I play your game:

Level 'LevelSelect' (6) couldn't be loaded because it has not been streamed in yet.
You need to ensure that levels which have not been streamed in yet are not loaded.

Should give you a pretty clear idea what is going wrong. The logs are fantastic at helping you figure out what is going wrong

(See http://unity3d.com/support/documentation/ScriptReference/Application.CanStreamedLevelBeLoaded.html if you need help.)

Thanks Graham, that’s really helpful to know and seems to have fixed the problem.