I downloaded this file, which introduces some different rules and modifications for the game. Where can I find quests which use these rules?

In Antistone's sig.

If you downloaded the standard zip file, the quest guide should be included in it; that's got 10 quests designed for Enduring Evil. If you didn't get it, you can download the whole package from my web site here:

http://www.mindflare.com/enduringevil/

thanks for the help, i found it