PROCEDURE:

1)first open blue ftp then browse to theme which i had given above........

2)Now click on that theme,contents inside the theme will be displayed

3)go to options>select all>extract selected items

4)now go to separate folder options>extract here
thus the files inside the theme.nth will be extracted in desired folder,close blue ftp

5)identify the wallpaper,screensaver etc....
usually you will find like this wallpaper.jpg,gridbg.jpg etc

6)replace those wallpaper,ringtone with your desired file ,but the name including extension of your file must be same as thems one ie..if themes wallpapers name is abc.jpg then name of your image must be abc.jpg only

7)now open blue ftp browse to the extracted folder options>select all>compress to .nth
it asks to enter the name of the file enter desired name but keep its extension as .nth only.....that's it you made your own theme