Black background on Trebuchet

On my current phone (HTC Wildfire S), with a AOSPA (Paranoid Android) 4.45 ROM, I installed Trebuchet, because Launcher3 lacks features, and other customs lauchers takes a lot of battery, while my current battery is already going down fast. Here you can see a screenshot of what it looks like:  The background is black. But it isn't supposed to be black:  How can I show correctly my background? Edit: Sometimes it show correctly on the bottom: