w3c html validation result - what does this mean?

[billwagnon]

... name="companyid" value="<%=Request.Form("companyid")%>">
^

Error: an attribute value literal can occur in an attribute specification list only after a vi delimiter


I'm trying to make my pages compliant with the check at w3.org



http://validator.w3.org/check

but I don't know what this error means