Paint Shop Pro :: Empty Histogram X3

I live in the American Southwest and during the summers here the light is very harsh, the skies are usually completely clear and there are few, if any, shadows at mid-day. A couple of days ago a large red-tailed hawk had landed on a tree near where I live and I had the chance to shoot a lot of (Canon 7D) RAW images of the hawk with the bright sky behind. After processing I found I was not happy with the way the photos came out with my usual photo software (Dxo and Elements , so I re-installed a copy of PSPP X3 on my computer and thought I would try to use layers to darken the sky without darkening the hawk (if I can figure out how to use layers...).

But I noticed that when I opened the histogram palette that there was no graph display other than what looked like a single stright line (with no width) in the center of the photo. I tried several other RAW photos and they were pretty much the same - sometimes empty, sometimes very, very small curves, but so low on the graph that it was easy to not even see them. I then tried some of the converted jpgs from Dxo and Elements 8 and they seemed OK. Visible histograms with normal height. The other software I have displays the RAW histograms normally. The distribution is not pleasant because there is such a bright background, but the curves are easily visible and of normal height. I began to wonder if there was some issue with PSPP X3 processing RAW Canon cr2 images that might be causing this problem for me.

My PSPP X3 is up to date with all service packs, but I can find nothing of this issue in the knowledgebase.