the solution to "failed to parse default light radius"
 

I will right now apologize if the solution is already known, but as far as I can tell, no one else knows it. Being very frustrated at my lack of having lights in any map, I went on a large search to find it, and here it is:
I created a caulk_nonsolid and set it at an unreachable spot in my map. I made it alone a func_group and gave it a key of light and a value of 5000. I then set a light where I wanted one, setting it to my desired value. The error "doom3lightradius: failed to parse...etc" did show up. But when I compiled my map with -light, the lighting worked. I tested with more lights, and it continued to work.
I hope this helps! :D
-Fox

Re: the solution to "failed to parse default light radius"
 

I have the same problem :). I think if you use a really quick build, the lighting screws up in game, but if you use the more advanced ones, it works out fine.

Re: the solution to "failed to parse default light radius"
 

Actually, my problem was also when I used a more advanced build. So it was like this huge thing to me when I discovered how to fix it =P.

Re: the solution to "failed to parse default light radius"
 

The quicker builds are for testing of the basic elements. Basically, there's a progression in which you're supposed to put things in - you add things to the map as each compile lists them, then use that particular compile for testing that element.

They work as a rough guide to the phases in which a map should be constructed.