rendering not working

When I go to render a frame, the render window often shows just a flickering image (which remains mostly empty). The render never really gets off the ground. This used to happen maybe 25% of the time, but lately it’s almost every time I try to render. I downloaded Blender again and re-installed, but no improvement occurred. (I’m using Blender 2.49B). My computer is an iMac OSX 10.6.4, Intel 2 Core duo, with an Nvidia GEForce 7600 GT graphics card. Thanks in advance for any help!

This happened to me when I was using 2.49 for a while on 10.6 – the render IS there, but you can’t see it properly until you toggle the image buffer. To do that, wait until the render is completed (which, of course, you can’t see – but you can monitor the numbers changing at the top of the render window, which will stop changing when the render is complete, or just take a guess after a while), then press the ‘j’ key twice. In my limited experience, this only happens with OS X 10.6 and I imagine no one is going to fix it since all eyes are on Blender 2.5, where the flickering doesn’t happen. Good luck!