query: wrong results

[Franziska Wenzel]

For testing purposes I've managed to get a map with London Boroughs
(area) 
and tube stations (points) displayed, on mapserver 3.3.011 for Linux.

But when I do a query on objects, either the borough layer or the tube layer,
I sometimes get wrong results. Tolerance for points is 5 and for area is null.
Within one borough different results are possible, a right one and wrong
ones which
names the neigbouring borough.

Any idea why this happens?

Is something wrong with my 
* coordinates (both maps and display are in carthesic coordinates)
* dbf-file 
or anything else known to cause this problem?

Thanks

Franziska