I've downloaded it fresh this morning, i get you about the website not being updated (it reports version 2.38) but the actual version installed is 2.40. 2.40 worked perfectly fine with mame 0.150 but they must have changed something in .151 as it stops working. The error i get in the cpwizard.txt file is:
[4392] 02/12/2013 12:51:46: ERROR @ MapMameInputToLabels (LayoutManager)
[4392] 02/12/2013 12:51:46: Object reference not set to an instance of an object.
[4392] 02/12/2013 12:51:46: at CPWizard.LayoutManager.MapMameInputToLabels(Layout& layout, List`1& layoutArray, Boolean layoutOverride, Boolean attemptReload, Boolean sub)