i'm working through a tutorial on xml and have the following code:
Code:
<?xml version="1.0"?>
<schema xmlns="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified">
<!-- We have a contact list called contacts that is a sequence of
  	 contact elements. Each contact element is a sequence of the
  	 elements firstName, secondName, age, gender, phoneNumber,
  	 emailAddress. The number of contacts in the list is unbounded.
-->

<element name="contacts">
	<complexType>
	<sequence>
	  	<element name="contact" maxOccurs="unbounded" >
			<complexType>
			<sequence>
				<element name="firstName" type="string"/>
				<element name="secondName" type="string"/>
				<element name="age" type="string"/>
				<element name="gender" type="string"/>
				<element name="phoneNumber" type="string"/>
				<element name="emailAddress" type="string"/>
			</sequence>
			</complexType>
		</element>
    </sequence>
    </complexType>
</element>

</schema>
this validates fine but without the maxOccurs="unbounded" it doesn't. It gives the error "The element 'contacts' has invalid child element 'contact'."

Would anyone be kind enough to explain this?