Problem with simulink model code generation

I am receiving this error during building simulink model:

Microsoft (R) Program Maintenance Utility Version 7.10.3077 Copyright (C) Microsoft Corporation. All rights reserved.

C:\Program Files (x86)\Microsoft Visual Studio .NET 2003\VC7\PlatformSDK\include\win32.mak(126) : fatal error U1050: Must specify CPU environment variable ( CPU=i386, CPU=ALPHA, CPU=IA64, CPU=ALPHA64) Stop. The make command returned an error of 2 'An_error_occurred_during_the_call_to_make' is not recognized as an internal or external command, operable program or batch file.

### Real-Time Workshop build procedure for model: 'mk100_cd4_model' aborted due to an error. !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!! Kompiliervorgang abgebrochen. !!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Error using ==> RTW.genMakefileAndBuild Error(s) encountered while building model "mk100_cd4_model"

I can't find anywhere hint, how to fix it. We are using Matlab 2006b and Visual Studio. Net 2003, and Windows 7 x64.