When attempting to log a Subversion repository you may get a "500 Internal Server Error" (via Apache), or "Could not access revision times" (via command line).
When svndumpfilter is used to filter revisions from a Subversion dump, the placeholder revisions have no date or time
To be able to do date ranged queries, you need the date to be set (as subversion does a binary search of revisions; hitting a null-dated revision breaks it)
The Subversion administrator (while a normal committer can do this, the pre-revprop-change script is managed on the server) must go through all revisions and set a date on them. The date needs to be set such that the revision ordering and date ordering is consistent.
The script DOES NOT make any changes to your repository. It just generates a script that can be used to do so