I have a free textbook exchange site I run using DBMAN at http://www.ezfindit.com/ezbooks

It's been running great for months. I recently tried to administer book posts as a user and when I click "Modify" after login, I get the error message: "Error: no matching records." despite the fact that there are 2 test records. I have duplicated the same problem with other user accounts also.

Here's the test account to try out:
User Id: test
Password: test

What could be causing it? How can it be fixed?

Any ideas would be very helpful. Thanks!

I'm attaching supporting files for reference.