Schema Validation Error (converted from Biztalk 2004 to Biztalk 2006 R2)

<?xml version="1.0" encoding="utf-16"?>
<xs:schema xmlns:b="http://schemas.microsoft.com/BizTalk/2003" xmlns="http://Project.Schemas.External.ScheduleRepair" attributeFormDefault="unqualified" elementFormDefault="qualified" xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:element name="schedulerepair">
    <xs:complexType>
      <xs:complexContent mixed="true">
        <xs:extension base="xs:anyType">
          <xs:sequence>           
            <xs:element name="customerremarks">
              <xs:complexType />
            </xs:element>
          </xs:sequence>
        </xs:extension>
      </xs:complexContent>
    </xs:complexType>
  </xs:element>
</xs:schema>

The schema above works on Biztalk 2004 however when compiled to Biztalk 2006 R2 an error below has been encountered:

Error 54 Wildcard '##any' allows
  element 'customerremarks', and causes
  the content model to become ambiguous.
  A content model must be formed such
  that during validation of an element
  information item sequence, the
  particle contained directly,
  indirectly or implicitly therein with
  which to attempt to validate each item
  in the sequence in turn can be
  uniquely determined without examining
  the content or attributes of that
  item, and without any information
  about the items in the remainder of
  the
  sequence.

Note that before the customerremarks field, there are optional fields/attributes/records which I just removed to simplify the schema. Please help!