This is a similar problem to "Having problem updating XCTU ver. 126.96.36.199 installer on window 7" July 17, by Wimpylicious. I did not see a good answer there. I got the installer file from www.digi.com/xctu as well as http://ftp1.digi.com/support/utilities/40003002_C.exe. Both .exe are same size (63.5Mbyte), so I assume they are identical. One answer from the previous forum hints that I have to have admin privileges to install. I don't have those privileges.
Anyway, if I try to install either, it tries to install Samsung USB Driver for Mobile Phones V1.3.550.0, fails then gives up.
My OS is Windows 7 either 32-bit or 64-bit. I just got the xBee WiFi Development Kit (two board of SB6, one SMT the other thru hole).