Animation problem (please help)

I am using blender 2.57 and made an animation consisting of 500 frames. I rendered this animation choosing a destination folder and using JPEG files. However half way through the render blender crashed. This was at frame 265. I changed the settings telling blender to start at 265 and end at 500. This worked and eventually all 500 frames were rendered. I then went to compile the animation and I got the message "error initialising video stream, does anyone know what’s wrong and how I might fix it? Thanks for the help in advance.

Try a different animation codec in the output settings. Also try a forum search for this error as I’ve seen it numerous times with possible other solutions.
Also I’d recommend not rendering the image sequence to jpg, these are lossy so you will be degrading your render quality especially after you then render to another lossy animation codec. Use a lossless image format such as .png

I looked at the settings and got it working. Thakyou for the help Richard, I don’t think I could have survived another 5 hours of waiting.

I got the movie to render but encountered yet another problem, I rendered in 24 frames per second but instead I wish to render 12 fps. When I saitch to custom frame amount and type 12 blender gves me the same error message as before. Any ideas how to fix this?