Well, global, I was able to reproduce our problem under different circumstances. This time was using a folder with backgrounds that i havent had any problems AT ALL, a very common folder i have been using. since it has not had this problem... till now.
Basically it boiled down to this... (Although i believe this situation has triggered this before, it was the suspect folder with lots and lots of backgrounds that i was using back then. This was a different folder). For FYI, all pics had no "weird" characters, or long filenames ect . "Fill" picture option, and timer at 3 min.
This happened when i had loaded 9 different IE windows, along with a torrent... bringing my mem usage up around 67%. This TIME, I hit flip3D to scroll thru webpages.... upon choosing one, that page popped up fine but with a black background, no pic, as desktop. Now, mind you, with Flip3D the background pic will show up clearly, and as an option to click of course, but when clicking the "background", it then shows up ( or doesnt actually) as... black.
Clicked every IE window to bring it up seperate, and everytime, background was black. Now while typing this, clicking flip3d now shows background window to choosen as black.
This slideshow is only shuffling thru about 10 pics, of which this hasnt happened for some days. Never has happened with this "setup" that i have now. My guesstimation of how long slideshow has been running would be about a day and a half (sys uptime). The picture in question has displayed numerous amount of times without any problems before.
So like i stated a few replies back.... I am thinking this has to do with somekind of buffer being overrun, saving mem for the system instead of displaying the background. IT turns "black" because that is the default background color fill of the desktop. This happened alot in win 98 days and actually XP if system was up for awhile and was in use of heavy applications. Ultimately having to reboot the system.
 wanted to add that this happened on XP and win 98 with the toggle of "show desktop" was used... sometimes just the once, sometimes after a few times of toggling.