how to import XSD types into root schema?

This is my existing XSD schema in foo.xsd, that declares just the type:

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" version="1.0"
  targetNamespace="foo">
  <xs:complexType name="alpha">
    <!-- skipped -->
  </xs:complexType>
</xs:schema>

This is another schema, that declares the element:

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" version="1.0"
  targetNamespace="foo">
  <xs:import schemaLocation="foo.xsd" namespace="foo" />
  <xs:element name="RootElement" type="alpha"/>
</xs:schema>

This is what I'm getting from SAX parser in Java:

"The namespace attribute 'foo' of an <import> element information 
item must not be the same as the targetNamespace of the schema it exists in."

What am I doing wrong?