I have had this same error on a file that had FAR too many items in the file. I started off by importing a dxf file of a building, then started adding tables, chairs, manaquins, etc, when after doing a test render, "Render Failed" came up. After re-booting the machine, (and saving the file,) I restarted C and opened the file to find the same error. AARRGGHH!!! So, I started all over agin, and as soon as I imported the dxf, I started elliminating all the empty groups, redundant groups, and other anomalies that had built up in the file. This time everything worked fine... on my PC. I also have a dual-1G Mac that I use for rendering, and as soon as the file opened in it, I had a "Render Failed" error again! AAARRGGGHHHHHH!!! I had to turn this file into a fly-through animation by morning, and compress it into an MPG AND upload it to my client.... oh yeah... and SLEEP! I went back to my PC, dropped the frame rate to 15 instead of 30, started rendering, set my alarm for VERY early, and went to sleep. Everything worked fine on my laptop, the client was happy, and I was a little bleary-eyed, but (sorta) happy. So, I hope my tale of woe helps you, in that you now know that... you are NOT alone. Murphy is ALLWAYS over your shoulder, waiting to strike fear, mayhem, and lack of sleep into ALL of our lives. ;>