When you build trough ojdeploy the task flow related files like page-template.xml, task-flow-registry.xml are not added in the deployed adf library.

to include that we have remove the entry in the ojdeploy snippet

<ora:parameter name="nocompile" value="true"/>

more information is here

http://one-size-doesnt-fit-all.blogspot.com/2010/11/using-ojdeploy-and-ant-for-creating-adf.html