Help with empty .chm output

When I choose File > Generate Primary Layout (Microsoft HTML Help), Robohelp goes about compiling a CHM file and reports that the build is successful. Click here to view output. When I view the output, the left contents pane is normal, but the right pane is empty. For the opening page, it says Can't display the page, but when I click a link/topic in the Contents pane, the right pane is totally empty. My HHC file is not read-only (as a KB article suggested). What's going on?

All of the HTML files in the project folder contain content and work fine. Seems like a TOC map thing.