错误：在PHP中调用SOAP cilent时，“对象引用未设置为对象的实例”

Here is the data from wsdl

这是来自wsdl的数据

<s:element name="CreateDraftLead">
<s:complexType>
<s:sequence>
<s:element minOccurs="0" maxOccurs="1" name="formId" type="s:string"/>
<s:element minOccurs="0" maxOccurs="1" name="FirstName" type="s:string"/>
<s:element minOccurs="0" maxOccurs="1" name="LastName" type="s:string"/>
<s:element minOccurs="1" maxOccurs="1" name="Gender" nillable="true" type="s:int"/>
<s:element minOccurs="1" maxOccurs="1" name="AgeGroup" nillable="true" type="s:int"/>
<s:element minOccurs="0" maxOccurs="1" name="MobilePhone" type="s:string"/>
<s:element minOccurs="1" maxOccurs="1" name="Birthday" nillable="true" type="s:dateTime"/>
<s:element minOccurs="0" maxOccurs="1" name="District" type="s:string"/>
<s:element minOccurs="0" maxOccurs="1" name="email" type="s:string"/>
<s:element minOccurs="0" maxOccurs="1" name="Region" type="s:string"/>
<s:element minOccurs="1" maxOccurs="1" name="LocationId" nillable="true" type="s:int"/>
<s:element minOccurs="1" maxOccurs="1" name="LeadSourceId" nillable="true" type="s:int"/>
<s:element minOccurs="1" maxOccurs="1" name="CompanyId" nillable="true" type="s:int"/>
<s:element minOccurs="1" maxOccurs="1" name="SourceCampaignId" nillable="true" type="s:int"/>
<s:element minOccurs="1" maxOccurs="1" name="AllowEmail" nillable="true" type="s:boolean"/>
<s:element minOccurs="0" maxOccurs="1" name="Questions" type="tns:ArrayOfQuestion"/>
</s:sequence>
</s:complexType>
</s:element>
<s:complexType name="ArrayOfQuestion">
<s:sequence>
<s:element minOccurs="0" maxOccurs="unbounded" name="Question" nillable="true" type="tns:Question"/>
</s:sequence>
</s:complexType>
<s:complexType name="Question">
<s:sequence>
<s:element minOccurs="0" maxOccurs="1" name="Key" type="s:string"/>
<s:element minOccurs="0" maxOccurs="1" name="Value" type="s:string"/>
</s:sequence>
</s:complexType>
<s: