Is the example for the same version of Excel you have? If not, you must change some ActiveX calls.
Instead of that, check where the error occurs, and see if something is wrong with the property/invoke node command, to see which parameters are accepted, check the object browser in Microsoft Visual Basic For Applications, and look for that command.
Making Excel visible sometimes helps finding problems.
If you don't find any problem, perhaps someone has the sollution, but first you should say which LV version you are using, giving the Windows version too.
First, I want to give you some details : I work with the LV 6.02 under Windows 2000.
I'm sure that the example corresponds to the correct version of Excel. The automation open occurs normally and the error appears just after the invoke node "application visible". With the other microsoft products, there is no problem... I don't understand that.