Deleting:
Click File, then click Quest Templates. Click the custom template and press the delete key. Confirm by pressing yes. That window reappears, this time without the custom template because you deleted it. Click cancel or click the "New Default (can't change)" and click OK, then ZQ crashed! After the crash, re-run ZQ. Look in the Quest Templates again. That custom template is there again.
EDIT: DarkDragon, I just felt like I want to do true splitting since you have made a new thread about the Loading part (under my username, that is). So if you want to see the Loading info: http://www.armageddongames.net/forums//thread/99052/. This thread is truly about Deleting. For Loading thread, follow the link to the new thread. I just want to let you know.