Forum Image Upload Manager - failure to upload
 

I've just upgraded from 3.4.8 to 4.0.3-P1 with surprising ease and success, compared to the initial trial runs on my test site.

The one issue I do have, that I did not encounter on the test site, is the Image Uploader is not working (uploads fail).
In both cases, I'm using GD, the server is not in safe mode, temp directories are set "/tmp" and permissions "777".
The problem is the same with Enhanced uploading on or off.

Any thoughts on where I should be looking.

Thanks,