diff -ru bugzilla-4.2-orig/Bugzilla/Constants.pm bugzilla-4.2/Bugzilla/Constants.pm
--- bugzilla-4.2-orig/Bugzilla/Constants.pm	2012-02-22 21:37:03.000000000 +0100
+++ bugzilla-4.2/Bugzilla/Constants.pm	2012-02-25 17:30:15.300985954 +0100
@@ -602,38 +602,34 @@
     #
     # On mod_cgi this will be a relative path. On mod_perl it will be an
     # absolute path.
-    my $libpath = dirname(dirname($INC{'Bugzilla/Constants.pm'}));
-    # We have to detaint $libpath, but we can't use Bugzilla::Util here.
-    $libpath =~ /(.*)/;
-    $libpath = $1;
+    my $basepath = '/usr/share/bugzilla';
 
     my ($project, $localconfig, $datadir);
     if ($ENV{'PROJECT'} && $ENV{'PROJECT'} =~ /^(\w+)$/) {
         $project = $1;
-        $localconfig = "localconfig.$project";
-        $datadir = "data/$project";
+        $localconfig = "/etc/bugzilla/localconfig.$project";
+        $datadir = "/var/lib/bugzilla/$project";
     } else {
-        $localconfig = "localconfig";
-        $datadir = "data";
+        $localconfig = "/etc/bugzilla/localconfig";
+        $datadir = "/var/lib/bugzilla";
     }
 
-    $datadir = "$libpath/$datadir";
     # We have to return absolute paths for mod_perl. 
     # That means that if you modify these paths, they must be absolute paths.
     return {
-        'libpath'     => $libpath,
-        'ext_libpath' => "$libpath/lib",
+        'libpath'     => "$basepath/lib",
+        'ext_libpath' => "",
         # If you put the libraries in a different location than the CGIs,
         # make sure this still points to the CGIs.
-        'cgi_path'    => $libpath,
-        'templatedir' => "$libpath/template",
+        'cgi_path'    => "$basepath/www",
+        'templatedir' => "$basepath/template",
         'template_cache' => "$datadir/template",
         'project'     => $project,
-        'localconfig' => "$libpath/$localconfig",
-        'datadir'     => $datadir,
+        'localconfig' => "$localconfig",
+        'datadir'     => "$datadir",
         'attachdir'   => "$datadir/attachments",
-        'skinsdir'    => "$libpath/skins",
-        'graphsdir'   => "$libpath/graphs",
+        'skinsdir'    => "$basepath/www/skins",
+        'graphsdir'   => "$datadir/graphs",
         # $webdotdir must be in the web server's tree somewhere. Even if you use a 
         # local dot, we output images to there. Also, if $webdotdir is 
         # not relative to the bugzilla root directory, you'll need to 
@@ -641,7 +637,7 @@
         # location.
         # The script should really generate these graphs directly...
         'webdotdir'   => "$datadir/webdot",
-        'extensionsdir' => "$libpath/extensions",
+        'extensionsdir' => "$basepath/extensions",
     };
 }
 
Only in bugzilla-4.2/Bugzilla: Constants.pm~
diff -ru bugzilla-4.2-orig/checksetup.pl bugzilla-4.2/checksetup.pl
--- bugzilla-4.2-orig/checksetup.pl	2012-02-22 21:37:03.000000000 +0100
+++ bugzilla-4.2/checksetup.pl	2012-02-22 23:08:46.620225264 +0100
@@ -49,8 +49,7 @@
 use Pod::Usage;
 use Safe;
 
-BEGIN { chdir dirname($0); }
-use lib qw(. lib);
+use lib '/usr/share/bugzilla/lib';
 use Bugzilla::Constants;
 use Bugzilla::Install::Requirements;
 use Bugzilla::Install::Util qw(install_string get_version_and_os 
Only in bugzilla-4.2/: checksetup.pl~