Suddely I cannot open a CS6 file

This morning I suddenly coldn´t open my *indd file any more - two days ago I worked with that specific file without any problems. Untill now I have unsuccessfully tried following actions:

1. Restart the computer
2. Restore my window 7-64 system to the day before, where I could work with that file.
3. Tried to open a back-up of the file
4. Installed InDesign 6 again
5. Try to open that file as a copy

In all these cases I still got this errormessage

I have seen the same question posted in August 2012 - but I saw  any final solution. Who can help me ?? What can I do ? My file size ist 4.5 GB consisting of 58 pages format DIN A3, where I have printet one side of a double-side paper.

CHB