I am trying to attach an 8M .wav file to a "story" in drupal. I can attach similar smaller files, but when i try this one and larger sizes i get in HTTP Error 0 message after a minute or to. I have checked all my max upload, Max Mem sizes they are set at well over 8M at 64M and 256M. Anyone else have this issue uploading files ever?
Maybe the script timeout is reached before the file is uploaded, try to set a higher maximum execution time for your php scripts.
The file size limits in php are upload_max_filesize and post_max_size, you can also try to increase those, see also http://drupal.org/node/97193
There seem to be a lot of possible reasons for this error, and the main problem is that Drupal core does not report any detail on AJAX failures - thus anything could be going wrong, but you're just seeing the "Error 0" text.
One possible way to diagnose this is to turn JavaScript off (for example, by using NoScript in FireFox) and try uploading again - then you may see the full error text, which will tip you in the direction of further investigation.
Some more discussion and some possible solutions (you'll see that there are many, since there are many possible causes to this problem) can be found here: http://drupal.org/node/297035?mode=2&sort=2