Custom color palettes disappear and won't reopen?

I have several user-defined palettes. They have functioned without a problem for the past year and a half. Yesterday, I closed CorelDraw. When I reopened it, they were all empty. I tried closing them and reopening them, still empty. I deleted them, restarted Corel, opened them through the palette manager... they still open up totally empty. I suspected maybe the .xml file was corrupt, so I have the color palettes on another PC at work. I resaved the palettes on those PCs, emailed the .xml files, opened on this PC, same problem: totally empty. Corel-defined palettes open fine, but custom-defined palettes always open empty. Any ideas what's going on or how to fix this?

You can see in the screenshot below that it is (1) checked under Window > Color Palettes, (2) the eye is open under the Color Palette Manager, (3) the window where the colors SHOULD be is open, and (4) some Corel-defined palettes are open with no problems.