Error. Please help?

I have an HP G6 running an AMD A8 processor. It has 8 gb RAM and runs on 64 bit operating system.
The problem has started since I upgraded to Cross DJ 4.1.
Once Cross DJ has opened up it asks me to plug in my Soundcard which is obviously the U-Mix Control Pro 2. As soon as I switch this on a message reads Error while opening "Mixvibes ASIO U-Mix Control Pro" Your device is already used by some other processes. Quit them all and retry.
I am not really a computer person so this message means nothing to me except causing me to get annoyed.
If I change the Cross DJ preferences to use the speakers and headphones, i get music coming out of the laptop speakers and I can use the keyboard to work Cross DJ but I have a controller that I want to use and I cant work out why this error message is coming up.
Please help?
Thanks in advance.
The problem has started since I upgraded to Cross DJ 4.1.
Once Cross DJ has opened up it asks me to plug in my Soundcard which is obviously the U-Mix Control Pro 2. As soon as I switch this on a message reads Error while opening "Mixvibes ASIO U-Mix Control Pro" Your device is already used by some other processes. Quit them all and retry.
I am not really a computer person so this message means nothing to me except causing me to get annoyed.
If I change the Cross DJ preferences to use the speakers and headphones, i get music coming out of the laptop speakers and I can use the keyboard to work Cross DJ but I have a controller that I want to use and I cant work out why this error message is coming up.
Please help?
Thanks in advance.