Fatal error…. wp-includes/query.php on line 27

Hi There

Looks like I have made a big booboo!

1) I tried to install the Beta Tester plug-in on my site
2) I have WP *MU* 2.9.2
3) The installation of the plug-in crashed and never completed and returned

Fatal error Call to a member function get() on a non-object in…. wp-includes/query.php on line 27

4) I manually deleted the WP beta tester directory on my server thinking it would resolve the issue

So now I can’t even log-in into wp-admin as all url will return this error message