The Nikon Scan software is not the most stable program in my opinion. I have been using it with Windows XP for a couple of years on two different computers and often got the same error message. Especially when doing batch scans.
About a year ago I got a new computer with Windows 7. As Nikon Scan will not run under Win 7 I searched the net and found a proposal how to make a change to the Nikon driver. After that change Nikon Scan hasn't crashed a single time.
By the way, earlier the nature photographer John Shaw had a very good article about setting up Nikon Scan together with either the Nikon Coolscan V or 5000, but I don't think the article can be found online anymore.
As some of the others mentioned, I also find there was a learning curve for using the Coolscan. Earlier I did most tweakings in Nikon Scan to get the best results, but now I have changed my strategy and scan the slides or negatives in best resolution and bit depth without many adjustments in Nikon Scan. Afterward I then do adjustments to the photos in Capture NX2 instead. I don't have much experience with scanning Kodachrome as only a few percent of the films I have scanned have been Kodachrome 64.