We had a power failure, that exhausted our UPS and subsequently shutdown our SVN machine. When it booted back up it, the system time was incorrect. Unfortunately, this was not caught until some people had already committed a changes. So now we have a few revisions that predate the first revision by several years.
Is there a way to correct this date, so things are in order?
The date/time is a property of the revision. Figure out the revision number (or use HEAD), and modify it with propset or propedit and --revprop.
svn propset svn:date 'YYYY-MM-DDTHH:MM:SS.MMMMMMZ' --revprop -r HEAD /path/to/wc/file
You'll have to play around with it to get the right combination of settings. You can also look at the Red Book, under Advanced Properties. (I linked to 1.4, adjust to suit your version).