I'm having the same problem. I've not uploaded any images for about a year or more and forgot my userid and password. When I enter the cachet (sp) code, my copy of zen photo states that it sent a password reset....which i never receive.
I checked other similar forum requests and one replied by sbillard contained this link "http://www.zenphoto.org/2007/12/troubleshooting-zenphoto/#16" which no longer links to anything. The response to this link was that it solved the problem.
The user guide documentation states that password table needs to be deleted and Zen setup run again.
Could some detailed steps be provided, with the needed SQL statements, that will reset this table. With instructions from "Login to the DB", to locate and delete the table, and finally to "Logout from the DB". Newbies .. like me.. need this.