[Mediawiki-l] Migration Problem

[Markus Karlsruhe]

I migrated from Version 1.5.5 of mediawiki to 1.6.8 and everything worked fine. After that i moved the database via mysqldump to a new machine and also the mediawiki directory via tar command.

Now I get an error like:
Fatal error: Call to a member function on a non-object in 
/home/test/public_html/includes/SkinTemplate.php on line 794

This is line 794 and the following lines:
  $revid = $wgArticle->getLatest();
                        if ( !( $revid == 0 )  )
                                $nav_urls['print'] = array(
                                        'text' => wfMsg( 'printableversion' ),
                                        'href' => $wgRequest->appendQuery( 'printable=yes' )


Any ideas??

Markus