I don't think you wanted to assign $IP as a local variable...

diff --git a/includes/installer/Installer.php b/includes/installer/Installer.php
index a8a641b..f849174 100644 (file)
--- a/includes/installer/Installer.php
+++ b/includes/installer/Installer.php
@@ -650,6 +650,7 @@ abstract class Installer {
         * Environment check for setting $IP and $wgScriptPath.
         */
        public function envCheckPath() {
+               global $IP;
                $IP = dirname( dirname( dirname( __FILE__ ) ) );
                
                $this->setVar( 'IP', $IP );
@@ -896,4 +897,4 @@ abstract class Installer {
                return false;
        }               
        
-}
\ No newline at end of file
+}