Please understand that someone provid hand held walk through every time one person wants something is quite labour intensive; better that you read some tutorials on linux, unix, command lines, terminals, shells, commands etc

However, here's a step by step:

Open X Terminal
type cd /usr/share/themes/ press return
type ls for a directory listing
decide which theme youre using (folder name) - alpha is the water splash, beta is the orange swirl, or maybe you have your own theme
type cd [FOLDER_THEME_NAME]/images/ replacing italics with relevant folder , press return
type mv ApplicationShortcutAppletPressed.png ApplicationShortcutAppletPressed.old to rename (move) the file
type mv ApplicationShortcutApplet.png ApplicationShortcutApplet.old to rename (move) the file

Suggest to write a mail to refunds@maemo.org to arrange a full refund of what you have paid for the support thus far