[DotNetDevelopment] The call is ambigous between the following methods error

[S]

public class DataUtil
        {
            public static ProductInfo GetInventoryInfo(string sku)
            {
                string filename = "Products.xml";
                XElement e = PackageUtil.GetXmlDocFromDefaultPackage
(filename); // This is the line I get the error.


            }
        }


namespace SLUtil
{
    public class PackageUtil
    {
        public static XElement GetXmlDocFromDefaultPackage(string
filename)
        {
            XmlReaderSettings settings = new XmlReaderSettings();
            settings.XmlResolver = new XmlXapResolver();
            XmlReader reader = XmlReader.Create("Products.xml");
            XElement element = XElement.Load(reader);
            return element;
        }

    }
}

The namespace above is at the top of the file and I am trying to use
the function but I get this error. Anyone know how to resolve this ?

Thanks,

All help appreciated