Using Office 2003 and Windows XP;

I need to call a program from a currently active XL file to another XL file;
I know you can a syntax like:

Application.Run "'FullFileName'!MacroName"

However, I need to supply an argument in this call, but the following
doesn't work:

Application.Run "'FullFileName'!MacroName(MyArgument)"

MyArgument is a variable name; how can this be done?

Thanks much in advance.