Unable to run cron : Call to undefined function contact_site_page()

After updating from 6.15 to 6.16....

Now, I am not able to run cron, when I tried to run cron manually, it displays contact page information(without theme) with the following error in last line:

Call to undefined function contact_site_page() in /home/user/public_html/includes/common.inc(1695) : eval()'d code on line 17

Error log says:
Cron run exceeded the time limit and was aborted.

I am using the php script in contact page

<?php
  require_once drupal_get_path('module', 'contact') .'/contact.pages.inc';
  print drupal_get_form('contact_mail_page');
?>

I removed the code & disabled the contact module, then tried again, same error appears

I also tried many times by removing code and clearing catches, but still the same error appears

Finally, I disabled the search and search404 plugins, again tried to run the cron no error displayed.

If I enabled the search module, not able to run cron..

Is there any solution to solve this?