Just posted the following on the Forum - Support - Post Installation Board. Thought it may be of interest to contributors here.
I have been getting Ajax requests terminating abnormally at odd intervals, and it has taken me quite a few days to tie it down. Mod_fcgid.c is central to the Fast CGI interface used for uploading images etc. The Default setting in fcgid.conf is for a maximum transfer of 131,072 - bits, bytes whatever. Thus MaxRequestLen = 131072. This needs to be significantly increased to handle image uploads in Drupal. A figure quoted elsewhere is MaxRequestLen = 15728640.
Setting max file size to 4MB is all very well, but if the fcgid can only transfer 256KB without returning an error to the Ajax handler then an Ajax alert will be generated. Currently running 7.26 so very relevant.
Alison