If I place a scene in the VSE and I put the start of the scene at frame 1 or more frames after the start of the animation; then blender stop rendering and I get an error saying "Error writing frame". This only happens with H264 output.

In the attached file the scene is placed at frame 3 and the animation starts at frame 1. Try rendering an animation. Notice that Blender will stop rendering at frame 24 (win7 x64) or frame 47 (Ubuntu x86). This changes depending on the OS and GOP size.

Tested on Blender 2.61 official (Ubuntu) and http://builder.blender.org/download/ rev 43149 (win)
Windows 7 64bit and Ubuntu 11.04 32 bit.
4GB ram
NVIDIA Quadro 1600M
T9500 Core 2 Duo @ 2.6 GHz.

P.S. Thanks for the quick responses and fixes. I guess I will have to start finding tougher bugs.
The average time I seem to wait for a bug fix is only ~24 hours! That has to be a bug!
You guys rock!