I've encountered this error in the past days at least a few times and it took me some time to research it and find the solution for it.
STORY: Your making a SVN commit, using Zend Studio, and the files are being sent but your PC gets stuck during the process/transaction and instead you get an error window that is telling you: "Commit failed. SVN E200030: There are unfinished transaction detected in ...", once that happens your entire local projects gets locked.
SOLUTION 1: Try doing a team -> cleanup, fallowed by a team -> update ... sometimes it might work, to me it didn't.
SOLUTION 2: Close Zend Studio editor. Go to your local project directory and open the .SVN folder and look for any .lock files and remove them, reopen the Zend Studio editor and do team -> update.
SOLUTION 3: Install DB Browser for SQLite. Close the Zend Studio editor. Go to your local project directory -> .SVN and open the wc.db file using the DB Browser for SQLite. In the DB Browser for SQLite go to: Execute SQL tab, and add there the following 2 queries, and run them one by one:
query1: DELETE FROM WC_LOCK
query2: DELETE FROM WORK_QUEUE
Now save the wc.db file, close the SQLite browser, reopen Zend Studio editor and run a team -> update.
In my case SOLUTION3 was the one that did the trick, I hope this was helpful.