can't compile

I am getting the following error:

[dcc32 Fatal Error] madIWSupport.pas(29): F2051 Unit IWAppForm was compiled with a different version of Vcl.Controls.TWinControl.CanUseDoubleBuffering

I use MadExcept and IntraWeb. I have installed and reinstalled. IWAppForm.pas is only in c:\users\toben\AppData\Roaming\IntraWeb 16\LibLazarus\source\public.

So I can't generate a new  IWAppForm.dcu