Currently the windows installer contains a component selection step. THe only possible option there is to either select or deselect the "sdk" component. This is highly unintuitive and does not change anything either way.
The fix is very simple and has been pushed here [1].
http://mitk.org/git/?p=MITK.git;a=commitdiff;h=14d143dfbdcbf6e0b77d40a70b28f0f77dcaa520