A really weird problem with querying a map

[Gregor Mosheh]

Hi, all. This is NOT your usual "why does my query template" not work 
question. At least I hope I've beyond that. :)

The map URL:
http://maps.hostgis.com/cincoenergy/XTO/
Login:  hostgis / hostgis
(yes, all layers off by default is intentional)
Turn on the Tracts layer.

The problem:
Use the Get Info tool and click the map to query the Tracts layer.
Chances are that "msQueryByPoint(): Search returned no results."

But if you keep clicking around, there are a few spots where it does 
work. For example, the larger blue parcel near the center: only the 
northeast side of this parcel can be queried. The angular orange parcel 
to the south of center: one can click-query at the vertex where the 
parcel curves, but not elsewhere.

Any thoughts on why querying this layer would exhibit such odd behavior?


Other information:

The locations which work stay the same between numerous queries and page 
reloads. It is not an intermittent problem, but is consistent.

This same application (with different data and locations) works 
perfectly, clicking and querying just fine. The URLs being generated by 
the clicks are pretty straightforward:
/cgi-bin/mapserv?mode=query&map=/maps/cincoenergy/XTO/mapfile.map&imgext=3744617.200913247+3949835.6361420923+3753465.8228735304+3956941.3477162593&imgxy=447+306&imgbox=447+306+447+306&imgsize=660+530&layers=Tracts]

The mapfile's layer entry is a polygon layer, with a query template 
defined. When it works, it works great. So I doubt that it's an issue in 
the mapfile.

-- 
Gregor Mosheh / Greg Allensworth
System Administrator, HostGIS cartographic development & hosting services
http://www.HostGIS.com/

"Remember that no one cares if you can back up,
  only if you can restore." - AMANDA