It looks to me that your mysql query is inconsistent with your database table structure. Look at your table prefix.users and see how many columns it has. The mysql insert query should have the same number of fields as the number of columns in your table prefix.users. Edit this line in your register.php and you will be able to fix your problem.
PHP Code:
runquery("INSERT INTO ".$prefix."users VALUES ('', '$username', '$pass1','$email','3','1', '$date', '0', '0' ,'','','','','', '{$GLOBALS['settings']['startmoney']}', '','$avatar', '', '', '', '1', 'Unknown', '')");