Bad element of type flashx.textLayout.elements::LinkElement passed to mxmlChildren

When I use this code:

    <s:RichEditableText x="20" y="100" color="#2b4381" fontFamily="Myriad Pro" fontSize="17" tabStops="S0 S50 S100 S150 S200 S250 S300 S350 S400 S450 S500" width="494" height="55" whiteSpaceCollapse="preserve">
        <s:textFlow>
            <s:TextFlow>
                <s:p><s:span color="#f77d0e"><s:a href="http://google.com"><s:span>some text</s:span></s:a></s:span><s:span color="#ffffff">posted 18 photos to</s:span><s:span> </s:span><s:span color="#0693ab">Web 2.0 Silicon Valley Design Team</s:span></s:p>
            </s:TextFlow>
        </s:textFlow>
    </s:RichEditableText>

I get the error, Bad element of type flashx.textLayout.elements::LinkElement passed to mxmlChildren

TypeError: Bad element of type flashx.textLayout.elements::LinkElement passed to mxmlChildren
    at flashx.textLayout.elements::SpanElement/set mxmlChildren()
    at Test/_Test_SpanElement1_c()[/Users/monkeypunch/Documents/test/src/Test.mxml:5]