Dimension3D's Poser File Organizer or Runtime Repair  are both excellent... the former more powerful maybe and the latter more simple to use. I have found no other tool that even touches Poser File Organizer for importance in correcting references, maintaining files and organizing runtimes. I use PFO to load all new content.

I don't know of a free solution aside from learning how to edit Poser files in EditPad Lite... a very powerful PC notepad that can handle HUGE poser files on multiple tabs with no slow down.