Continua a non trovare il file header window.h

Ho aperto il file wx.dsw.
L'ho convertito ed ho provato a compilare il primo progetto.
Questo l'esito:

codice:
------ Build started: Project: adv, Configuration: Debug Win32 ------
Compiling...
dummy.cpp
c:\Documents and Settings\user\Desktop\wxWidgets-2.6.3\include\wx/msw/wrapwin.h(51) : fatal error C1083: Cannot open include file: 'windows.h': No such file or directory
Build log was saved at "file://c:\Documents and Settings\user\Desktop\wxWidgets-2.6.3\build\msw\vc_mswd\adv\BuildLog.htm"
adv - 1 error(s), 0 warning(s)
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
IL solo "progetto" che viene compilato correttamente (warnings a parte) e' wxregex

Sigh...