How do I nail furring strips without them cracking?
You may be using the wrong load.  This site recommends using a Yellow #4 load on strips 3/4" thick, or Green #3 for 1/4" - 1/2".  

You could also use concrete screws.


Pre-drill holes in furring strip and wall (about every 24").
Clean holes in walls well (with shop-vac).
Using concrete screws fasten furring strip to wall (do not over tighten).