Solution 1:

This is probably due to an issue with Finder. Relaunch finder with the following command in terminal:

killall -HUP Finder

Solution 2:

In addition to the Unix file permissions, there are old HFS file bits. To unlock your folder try:

Terminal > chflags nouchg ~/sites/lockedfolder

Alternatively, you could do a Get Info in the Finder, and uncheck the "Locked" checkbox from that window.

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Solution 3:

Download BatChmod, free and very, very handy.

When one is done working, correct permissions are easily restored.