From time to time, critical bugs are found that dictate a patch be created to fix them instead of waiting for a new release of the product to come out.
This page will make such fixes available to registered users of this site.
All you need to do in most situations is to copy the file required down to your system and place it in your Birder's Diary /data directory. By default this would be c:\program files\birders diary\data\.
If the fix comes in a ZIP file, you will need to UnZIP or Extract it after downloading and then run the EXE that was extracted.
Only download and run these files if you know you have the problem indicated.