can't access admin panel

Dear All ,

   I am unable to access my admin panel , i run debug utility , found below error , 

[12-Apr-2009 20:30:39] PHP Fatal error: Call to a member function Execute() on a non-object in /var/www/vhosts/zainisupplies.com/httpdocs/includes/functions/sessions.php on line 61

Plz anybody can help me on it ,

what version of zencart are you using ?
what version of PHP has been installed on your server. ?

PHP Info
PHP version: 5.2.9
PHP API version= apache2handler
PHP Safe Mode= OFF
PHP Register Globals = ON
PHP set_time_limit (max execution time) = 30
PHP Disabled Functions =
PHP open_basedir = /var/www/vhosts/zainisupplies.com/httpdocs:/tmp
PHP Sessions Support = ON
PHP session.auto_start = OFF
PHP session.use_trans_sid = OFF
PHP session.save_path = /var/lib/php/session
PHP Magic_Quotes_Runtime = OFF
PHP GD Support = ON
PHP ZLIB Support = ON
PHP OpenSSL Support = ON
PHP CURL Support = ON
PHP File Uploads = ON
PHP File Upload Max Size = 12M
PHP Post Max Size = 12M
PHP File Upload TMP Dir =
PHP XML Support = ON
PHP FTP Support = ON
PHP PFPRO Support = OFF
PHP Sendmail_FROM =
PHP Sendmail_PATH = /usr/sbin/sendmail -t -i
PHP SMTP Settings = localhost

i dont know how to check my zen-cart version , i install it on my server in year 2006

you may want to look at this solution ..

http://www.zen-cart.com/forum/showthread.php?t=71393

fixed now , thanks for suppurt