CentOS 5 Server :: PHP SOAP Server Returns Array Using NuSOAP Library?

I have a function in my SOAP server that returns an array. When the client calls this function, it only receives "array", and when I use foreach to print each member of this array, it tells me that this is not an array. If I change the returned value of the function to a string or integer type everything works fine though, so I don't think that there is any problem with the client.I am using NuSOAP library on php to achieve that.I had doubt when declaring the type of return value of the function. In XML schema there is no array type, so I specified the return value as a string like this:

PHP Code:
$server->register("getLocation",
array('country_population' => 'xsd:string',

[code]....