Weird System Prefs Bug 10.5.3

So after 10.5.3 was released i decided maybe it was time to switch over to Leopard again (i upgraded initially then downgraded back to Tiger). After installing leopard (clean install) and transferring everything over...manually!...

...I decide to change my default desktop picture from Aurora to something a little more my taste and discovered a weird bug. Anytime i try to point system prefs to my 'wallpapers' folder in my Pictures folder, it says the folder is a duplicate yet when i look at the source list, wallpapers folder is missing with only an Aperture projects folder being visible (doesn't contain wallpaper folder either). Also, clicking on the Pictures folder itself draws a blank

The only way to get wallpaper folder to show up, is to DELETE my Aperture library in its entirety from the Pictures folder. This will then let me select the folder and it'll appear in the source list. However as soon as i launch Aperture again and a new library is created, the issue reappears. Obviously this isn't ideal, i dont want to be deleting my library just so i can change my desktop picture. Pictures of the situation are shown below.

Anyone else have this issue?

 

Thanks i'll try it out when i get home