Excel 2007

I have a problem that has been driving me nuts. I created a code module and
have pasted a couple of user defined functions into the module. When I am
entering my formula into a cell and I start typing the name of the function,
I see that the function is listed in the drop-down list of functions. That
tells me that Excel recognizes the function. However, after entering the
formula I get a #NAME? error.

Here is a link to just one of the user defined functions that I've been
trying to use.

http://xldynamic.com/source/xld.ColourCounter.html#code

Other people have successfully used the function as-is without any problems
by doing exactly the same things that I've done. Yet, when I try to use the
function I just get the #NAME? error. Furthermore, I've tried a number of
different functions and with every one I get the #NAME? error.

Is there something that I need to do in order to use custom functions, like
maybe install an add-in or something, or is there a configuration setting
that enables the use of custom functions?

Thanks for any help that you can offer.

--Tom