Try opening the files "as a copy," but don't hold your breath. Error code 5 is pretty much a non-recoverable error without outside tools.
If you have the time, you can rebuild the files, or you can use the Quark method. Markszware, the maker of the plugins for ID and Quark that are required (in additon to a copy of Quark Xpress), offers a recovery service. See Bad InDesign or Quark File Recovery Submission Form
I'll try. Right now Im rebuilding them from the ground up.
Thankfully I have printouts of my last save. I scanned them and now
I'm recreating the file as close to how it looked.