You could also use the Inno Setup action, specifying the /s parameter in the Additional options field on the Options tab, but either way, the error is coming from the signing tool, not Visual Build, and Visual Build itself does not open the setup executable file, so there must be a conflict between signtool and iscc (or some other program using the file).
http://www.kinook.com/VisBuildPro/Manual/innoopttab.htm
http://www.kinook.com/Forum/showthre...?threadid=3044