First, Thank You!
Now … some suggestions:

In order to hunt down those pesky critters we just need an example of how to reproduce the bug.

Poor Example

I can't get into the book my roommate Justin invited me to. It just says Application error. I am trying to get in from the dashboard area.

Great Example

1. I was invited to the book "Justin Lakes."
2. I was on this page: http://memorypress.familylearn.com/bookshelf
3. I clicked on this page: http://memorypress.familylearn.com/bookshelf/1991/editor
4. The screen was blank.

In the poor example, we don't know the url (the part that begins with 'http://') that produces the error. We don't know what book Justin created. We can't reproduce it. In the good example, we receive the steps that lead to the error as well as the urls to reproduce it. Thank you again for taking the time to help us squash these bugs!