I couldn't get Till's Chimera pack to import, but I just figured it out. The FILE PATH needed to have the ' (that's an apostrophe) character removed. However, it was because it was one of those slanted apostrophes, not a normal one (I'm sure this was M$'s fault at some point in the line). I replaced it with a normal apostrophe (using Windows Explorer), and they imported fine.
The FILE NAME of each rig also have an apostrophe, but it's the normal kind, not the @#$@#$@#$ slanted one. I tried it every possible way and that was the issue.