I\'m running WP 3.0.1 on a shared host using PHP5. I\'m having issues uploading files that are a little larger via the media uploader in the admin section of WP.
Eve
For me, "http error" issue occurred when php is running in fast cgi mode.
"MaxRequestLen" from mod_fcgid was limiting file upload size and wordpress was throwing "http error".
You need to add the following configurations in your httpd.conf (apache2.conf on ubuntu 14) :
# 20MB MaxRequestLen 20000000