fresh phpbb2 install
fresh premodified 2.0.22 install
fresh mysql 3.x db
phpbb2 is working great
attachmod seems to be working great until you actually try to attach a file. When I do my browser kicks back "The connection was reset"
It might have something to do with your max_execution_time set to 30 seconds. In that case you would need to have that value increased. Does this happen with any file you try to upload?
Look for the setting in the php.ini file then and increase it. Normally it's set to 120. Not sure where that file would be located at on a Linux/Unix server though...
Can't remember if this is in your php.ini file or in the MySQL setup files but you should also change mysql.connect_timeout (make it 60).
Also I noticed that upload_max_filesize is set to 2M which seems to be at about the size of your file. Make it 20M, restart Internet services if required, and you should be good to go.