this is the reason the "svn diff" command fails?
Yes, if you have TortoiseSVN version 1.5:
How to verify this:
1. Create empty folder, and download CHDK using command-line svn client: svn co ht_tp://tools.assembla.com/svn/chdk/trunk/ .
2. .svn/format is 8, and command-line svn client works well.
3. Touch this folder using TortoiseSVN (for example, using "update" command) - after this .svn/format is 9 and command-line svn client fails: "I'm too old for this sh@t"