It thinks the file is installed to the Poser application folder. That isn't a hard-coded path from the content or it wouldn't work for anyone, but by the number of items missing icons and with an exclamation mark in your screenshot DS still thinks al lot of files are installed there from a previous attempt when you presumably did have that as your destination (in 4.8 the database is always using absolute paths). You need to reinstall the Default Lights and Shaders using the correct path, as in your DIM screenshot, and make sure they are working, then you can tidy up the orphan references by using the Content DB Maintenance command in the Content Library pane's option menu - the lined button in the top corner, or right-click the tab.