yay, I was having the same problem that 3java3 had with my new Windows 7 computer and brand new updated version of Windowblinds.
but followed Mrsguy's advice on this old thread and now the issue is resolved 
In my case, none of the Windowblind's would apply whatsoever-- but would just turn my pretty Aero taskbar this plain white color. Only system restore would bring it back to the Aero transparent look.
On Windowblind's "About Screen" it even stated that Windowblinds was "installed correctly" too. When I tried to apply a theme, after following Mrsguy's advice, a little box popped up on the screen stating something like: "Windowblinds was not installed correctly, would you like to fix this". I clicked "yes", and then it applied the skin - Wouldnt work whatsoever before this. These forums are great help- my issue was resolved without having to bother the Stardock folk..yayyyy! thanks MirsGuy !
ps... lov'n my Windows 7 by the way-