Trouble with exporting finished track

[DanTraX]

Gday All
I'm having trouble rendering my finished track.
I have been using Ableton for some time and am familiar with how to export (render)
This is a problem I haven't come across before.

After going though the process of rendering there is no sound coming from the wav file in Itunes (other music plays ok)
and the track it self that is still up on the arrangement page will not play through the "master" channel . Although all the level indicators are flashing in all the other channels.
The only way to get it working again is to reopen the track again and all works fine.

If tried freezing some track, normalize on or off, and as a AAIF.
I run a mac book pro with leopard any help would be fantastic

Regards Dan

[Cezband]

Are all the tracks routed to the master channel? Nothing set to solo or anything?
If not, any 3rd part VSTs in there, especially on the master channel? Could just be a VST being buggy...