Cron run fails with Error 500 Internal Server Error

same issue here....

There can be many reasons. In my case it was the number of items to index on each cron run. I lowered it and the error disappeared. Do so on admin/settings/search.

But I still don't know which setting causes this error.

php is timing out (max_execution_time) because the reindex time is too long. Decreasing the number of items to index will overcome this issue. Or increasing the max_execution_time setting will help also.

If this issue is resolved, please set this issue to closed.

same issue here...., how to fix it? thanks a lot.

if you can, try running cron using drush

After running "sudo drush cron", I got the following:
PHP Fatal error: Call to undefined function views_build_view() in /var/www/html/../drupal-6.22/includes/common.inc(1696) : eval()'d code on line 6
Drush command terminated abnormally due to an unrecoverable error. [error]
Error: Call to undefined function views_build_view() in /var/www/html/../drupal-6.22/includes/common.inc(1696) : eval()'d code, line 6
WD cron: Cron run exceeded the time limit and was aborted.

Well, now you know that there is a problem with Views. Check for available updates on your modules.

Also, you can configure your php.ini to increase the max_execution_time. In ubuntu it would be something like /etc/php5/cli/php.ini