Well, i mentioned in my last post that i installed media wiki for berrydev.net but failed to mention the struggle to get there.
I went to install 1.5.5 (latest stable) figuring it would be ok. I swear they didn’t test the install. Note: this was a completely blank domain. no conflicts were possible.
Step one: add maintainance into the installer’s include path. in /config/index.php, edit line 118 and add $sep$IP/maintenance into the include path (new line: ini_set( "include_path", ".$sep$IP$sep$IP/includes$sep$IP/languages$sep$IP/maintenance" );)
Step two: edit the dbsource function. they seem to assume aliasing or something. either way, we need slashes and better references to files. insert after line 94 (so this becomes the first few lines in the function):
if(!preg_match('%^/.%',$fname)){
  $fname = dirname( __FILE__ )."/".$fname;
 }
(probably optional) Step three: insert the contents of InitialiseMessages.inc into updaters.inc. Just copy/paste the first into the end of the second. for some reason, my server would not include the file right so i was getting “funciton not found” fatal errors. it fixed it so… eh.
in case anyone else is having problems installing it, that was what I ended up doing and all worked.