Close Mach then browse to the Mach3 folder and double click on the DriverTest.exe to see if your driver is installed properly.
If it is and you pass the test then please attach your xml file and we can have a look and see if we find any problems. To attach your xml you will need to use the reply button then choose the additional options, you will also need to copy your xml to another loactaion on your computer and rename it or the forum will not allow you to attach it, something like mattdaniels.xml should work fine.
Hood