IIRC, it was Java related.
http://prc.athasreborn.com/index.php/topic,1442.msg6076.html#msg6076There are tons of threads on it. Use the PRC search and type "Creator." I could not find immediately.
I remember trying the fix, but it didn't work for me. I still have the same issue. Also, recent Java "upgrades" have toggled functionality here and there.
I can't mod the skins, but there is a way you can still finalize. Below the "Tattoo Customization" button on the left is a box with a couple of dots. If you click that, you can finalize. Workaround, not a fix.