The latest beta (2.4.581) you provided also did not fix the problem for me. I have made sure my Mac is completely updated (10.10.1). I’ve also tried it on another MacBookPro in our office (I work for an IT department at a school district) that was just fully wiped with a new, clean install of OSX 10.10.1 with the same results.
I made sure and removed the old installation of NetSpot 2.4.580 before upgrading to 2.4.581 just in case the problem was in overwriting the existing install, but again, no difference.