Unable to generate a temporary class (result=1). CS0266

Question

I am getting this error only on one test server but the code works on other servers as well as my dev machine.

    Unable to generate a temporary class (result=1).
    error CS0266: Cannot implicitly convert type 'xxx.xxx.xxx.xxx.MessageHeaderMessageId?'
 to 'xxx.xxx.xxx.xxx.MessageHeaderxxxCode?'. 
An explicit conversion exists (are you missing a cast?)

Here is a sample of the wsdl for the MessageID.

<xsd:element name="MessageId" nillable="true">
  <xsd:simpleType>
    <xsd:restriction>
      <xsd:simpleType>
        <xsd:restriction base="xsd:string">
          <xsd:whiteSpace value="preserve"/>
        </xsd:restriction>
      </xsd:simpleType>
      <xsd:enumeration value="xxx"/>
      <xsd:enumeration value="yyy"/>
      <xsd:length value="8"/>
    </xsd:restriction>
  </xsd:simpleType>
</xsd:element>

Answer 1

See http://nishantrana.wordpress.com/2008/02/06/unable-to-generate-a-temporary-class-result1-error-cs2001-source-file-cwindowstempfilenamecs-could-not-be-found-error-cs2008-no-inputs-specified/

Answer 2

Found the issue. The server did not have the .Net Framework 3.5 Service Pack 1 so we installed that and it start working. Thanks again Simon for responding.