Never rename a skin in skin studio. Save it as a different skin name instead. Then, never ever just rename the folder afterwards. Why you dare ask... here's why...
When you try to open it again in skinstudio, it will ask if you wish to overwrite the files..
If you choose the stupid path, you will say yes to this daunting question and alas, every little piece of graphics that YOU SPENT DAYS AND DAYS ON will be forever lost.
(see post #43 in the message thread titled March Desktop Screenshots to see what I lost)