[support] question about CiviCRM

I've been using CiviCRM for almost a year now with Drupal and I LOVE it! However, I've never been able to upgrade from the 3.1.5 I started out with! Everytime I get some sort of error with the database and I have to go back to the 3.1.5 version. Does anyone use it who can offer some advice on what I do?

This last time I got these type errors when I ran the upgrade script:

warning: include <snip> sites/default/files/civicrm/templates_c/en_US//%%06/06C/06C5296F%%jquery.fil es.tpl.php) [function.include http://mana.org/drupaltest2/civicrm/function.include ]: failed to open stream: No such file or directory in <snip> /sites/all/modules/civicrm/packages/Smarty/Smarty.class.php on line 1263.

Thanks,

Tina