That error may be a control (item in the tool box) missing in your edition of excel. I have a couple computers here at work that do that. Still working on that...it works fine on all of mine(XL2003/XP and XL2010/Win7), so I'm not sure exactly what is causing that.
Other than the calendar issue, it works if you type in the dates on the other computers here at work.
I'm not anywhere near any point to where I'm calling myself a whiz in Excel or VBA
....I'm still learning what it will and will not do.....I find it amazing, so it keeps me interested in learning it.