Hm. I've only compiled monolithic versions for PND deployment (add -DPANDORA to cmake flags) for some time, so there's a possibility the regular compile/install is not up to scratch. As far as I know installing has worked before for Panorama (which is the UI platform used by PNDManager), so it sounds strange that it wouldn't work now. In monolithic compiles the interfaces dir is of course right next to the executable, which it seems to assume in your case. You could do a monolithic build, stick that to /usr/share/pndmanager or something and just symlink to the executable from /usr/bin. It's a bit less ugly hack than adding stuff to /usr/bin.