Help to build a theme|PS3 Themes|Forum|PS3 Themes

I have downloaded and installed the PS3 Theme builder, but i can't build a theme. I can do everithing to create the theme, and also I can save the .xml filebut when I try to "build" the theme , the computer says that there is an error.It opens a kind of "console" window where it says that I can't write in the folder.
So, i was wondering if someone here could said me how to solve this or if someone could compile it instead of me