e_dmc2, Firstly do not try to load a pre-modded firmware to your player it will most likely kill it. Always mod your own firmware. The themes you have chosen may not match the image layout of your players firmware exactly so you may have to edit some images to suit.
You need to first extract your firmware from your player using s1fwx.
Download
HERE
Guide
HERE
Then you can change the images using s1res
Download
HERE
Guide
HERE
Then reload your firmware to your player using MP3 Player Utilities Update Tool
Download
HERE
Guide
HERE