using access 2007 and excel 2007, can't run a macro in excel from access

here is the error message: "The macro may not be available in this workbook
or all macros may be disabled."

the workbook that contains the macro is in a location that is trusted by
both access and excel

here's the code:
module level declaration
Private ExcApp As New Excel.Application
procedure code
the following works
ExcApp.Visible = True
ExcApp.Workbooks.Open FileSpecification
(the AutoOpen macro runs ok here)
ret = ShowWindow(ExcApp.hwnd, SW_RESTORE)
ret = MoveWindow(ExcApp.hwnd, L, T, R, B, True)
this doesn't work (see error message above)
ExcApp.Run "MacroName"

can anybody help?