I have recovered SVN repository from crashed PC and now I can checkout files from few directories but in one place during checkout it says:
Error: REPORT of \'/s
For us, the problem was missing files in the SVN history (probably disk corruption). Any operation including a file whose most recent change was from the missing section of the history would fail with this "could not read chunk size" error, or an invalid XML error (depending on the operation). Fortunately we had a backup which included the missing files. Restoring them fixed the problem.