I get this error when I do an svn update:
Working copy XXXXXXXX locked Please execute \"Cleanup\" command
When I
I came across the exact same issue using SVN 1.7 and none of the fixes mentioned above worked.
Foremost, make sure you backup all your edited content.
After spending a couple of hours (didn't redownload everything as my branch is over 6gb in size), I found that there is a db file called "wc" in the .svn folder of your branch.
Open up the db file using any db manager (i used firefox's sqlite manager plugin) and navigate to WC_LOCK table. This table will have the entries for the acquired locks. Delete the records from the table and you're done :)