This program allows you to restore some InDesign documents that can’t be restored automatically. The current version of the program checks the integrity of the document’s block structure and corrects it. In some cases this allows you to repair a file which InDesign is unable to open with Error code:5.
The program worked very well for me: all the damaged files were successfully restored. Thanks to the author — Mikhail Kondakov— for it.
Here is the original link for downloading it, and here is the web-page with brief explanation (in Russian). I translated only the beginning, if someone is interested, I can do the rest.
I also made it available for downloading from my site since the original link gives a warning in Russian which might be confusing.