: <lst name="defaults">
...
: <lst name="appends">
: <str name="fq">{!switch case='*:*' default=$fq_bbox
: v=$fps_latlong}</str>
: </lst>
: <lst name="invariants">
: <str name="fq_bbox">_query_:"{!bbox pt=$fps_latlong sfield=geo
: d=$fps_dist}"</str>
: </lst>
: </lst>
...you have your "appends" and "invariants" nested inside your defaults --
they should be siblings...
<lst name="defaults">
...
</lst>
<lst name="appends">
...
</lst>
<lst name="invariants">
...
</lst>
-Hoss
