OGC-Filter in GetFeature request

[Dmitri Mizerkin]

Hi list,

I'm trying to send a WFS GetFeature request to the Mapserver, applying a
ogc-filter on the features to be included in the response. Though, I get an
error message in the response stating "msWFSGetFeature(): WFS server error.
Invalid or Unsupported FILTER in GetFeature". 

My request is:
http://localhost:8080/cgi-bin/mapserv.exe?map=/ms4w/apps/Avenida/htdocs/Avenida.map&layers=Achse&REQUEST=GetFeature&SERVICE=WFS&VERSION=1.0.0&BBOX=2574985.815002%2C5643233.501443%2C2587295.900005%2C5658111.118461&TYPENAME=ms:Achse&MAXFEATURES=10&amp;FILTER=<ogc:Filter%20xmlns:ms="http://mapserver.gis.umn.edu/mapserver"%20xmlns:wfs="http://www.opengis.net/wfs"%20xmlns:gml="http://www.opengis.net/gml"%20xmlns:ogc="http://www.opengis.net/ogc"%20xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"%20xsi:schemaLocation="http://www.opengis.net/wfs%20http://schemas.opengis.net/wfs/1.0.0/WFS-basic.xsd%20http://mapserver.gis.umn.edu/mapserver"><ogc:FeatureId%20fid="Achse.180"/></ogc:Filter>

Has anybody an idea what could be wrong?

Cheers,
Dmitri Mizerkin