Installation error the parameter is incorrect

We are attempting to install a cluster for further SAP installation. I have
read the following article:
http://support.microsoft.com/default...b;en-us;302491
I get this exact error message but (as far as I can tell) I have no invalid
characters. The ipAddresses string = 10.10.0.18,255.0.0.0,Public
Can anyone help (I'm a bit baffled at the moment!)
Thanks
I have now worked out what the problem is. There is another cluster with
"Public" defined. Have changed this to something else and it now works.