Again, sorry for the delay, but I have found a way to make the text black for you
I got this from another site, and it works.
*Make sure you de-select
"use drop shadows for icon labels on the desktop".
*Now, right click, go to personalize, then go to desktop background, then go to solid colors. Click white background, apply. The text will have changed to black.
*Now go back to select the picture that you want to be your background.
Note that this works until you select drop shadows again - at that point you're back to white. No drop shadows, but at least you can have black text!