From what I know the tag should be:
<sc:text ID="id" Field="FieldName" runat="server" />
What I'm missing in your code is the runat="server"
tag and I don't see an ID.
Further you should be aware that all items related to this field should be published. That is the Template and - if there is one or more - subtemplates and the item which contains the field itself. Also when you checked all of this you can try switching the database to WEB in the desktop environment to see wheter the information for your field has been published for sure.