Apple - Can't change folder permissions
In addition to the Unix file permissions, there are old HFS file bits. To unlock your folder try:
Terminal > SetFile -a l ~/sites/lockedfolder
OR
Terminal > chflags nouchg ~/sites/lockedfolder
Alternatively, you could do a Get Info in the Finder, and uncheck the "Locked" checkbox from that window.
This is probably due to an issue with Finder. Relaunch finder with the following command in terminal:
killall -HUP Finder
Download BatChmod, free and very, very handy.
When one is done working, correct permissions are easily restored.