You need to know what's the name of the file that this mod is trying to find and in what folder is this. To do that simply right-click on no-image space and copy the image path, this will show you the location of the image.
Now, you can do a image or use other one simply uploading by FTP to the path and rename it whit the name Thank-O-Matic use (I think is thank_you_b.gif)
Sorry for my bad English but I'm spanish, I hope you understand me
