[OpenLayers-Dev] ArcGIS + OpenLayers connection problem

[Holmes, Charles V.]

I'm having trouble connecting to our ArcGIS server that is running with
a map titled WorldImage.  The problem seems to boil down to the WMS we
setup not recognizing the layer type "basic".  The error is something
along the lines of "Parameter "layers" is not recognized" and no tiles
are returned

var wmsLayer = new OpenLayers.Layer.WMS( "Our WMS",
"http://server/arcgis/WMS", {layers: 'basic'});

What should layers be called?  Is there a way I can tell from the WMS
I'm running?  

This is being deployed in a closed lab, so that is why I don't have
exact error messages, etc.  I also can't give instant feedback about
whether a certain approach works, so if anyone could just throw out
ideas, I'd like to hear them.

--
Charles Holmes
Software Systems Engineer
The MITRE Corporation