Works perfectly for me.
Code:
Sub TryIt()
Selection.TypeText ConvertCurrencyToEnglish("234.56")
End Sub
And I get:
Two Hundred Thirty Four Dollars And Fifty Six Cents
I did have to carefully clean up the copy and paste from that web page. It added a whole bunch of spaces. But the code works in Word. There is no syntax error in the code itself. If you are getting one there is something wrong with the text you are using.