My b2evolution Version: Not Entered

I upgraded my b2evolution blog, but now I can't access the admin area.

Can someone please help ? This is the message that I've been getting.

Thanks

Notice: Undefined variable: admin_dirout in /home/victorhu/public_html/blogger/admin/_header.php on line 17

Notice: Undefined variable: core_subdir in /home/victorhu/public_html/blogger/admin/_header.php on line 17

Warning: require_once(/home/victorhu/public_html/blogger/admin///_main.php) [function.require-once]: failed to open stream: No such file or directory in /home/victorhu/public_html/blogger/admin/_header.php on line 17

Fatal error: require_once() [function.require]: Failed opening required '/home/victorhu/public_html/blogger/admin///_main.php' (include_path='.:/usr/lib/php:/usr/local/lib/php') in /home/victorhu/public_html/blogger/admin/_header.php on line 17