For the past few days I have been working with SOAP on a number of platforms. I wanted to use NuSoap with PHP5 and here are a few steps which will allow you to do so. As PHP5 has an inbuilt support for webservices it will clash with the names in nusoap.php. To get over this rename the class soapclient to soap_client. Also rename the constructor soapclient to soap_client.
This is all that needs to be done. Once you do this you would be able to run NuSoap with PHP5.