web mapping - Access-Control-Allow-Origin error in web map

I am having trouble getting a WFS layer working using Geoserver, OpenLayers and GeoExt.

I get the following error:

XMLHttpRequest cannot load http://10.0.0.155/geoserver/wfs. Origin http://10.0.0.155:8080 is not allowed by Access-Control-Allow-Origin.

Does anyone know how I get around this? I can't find anything in the examples for geoserver, openlayers or geoext.

I don't get any errors when using WMS on my maps.

Many thanks,

James

Answer

I think this is this problem http://trac.openlayers.org/wiki/FrequentlyAskedQuestions#ProxyHost

so you need to set up a proxy host as per those instructions.