No response: ( object = class org.geoserver.wms.map.RenderedImageMap ) Error

Hi There,

I was trying to setup and view the HeatMap for the accident points i have using the Acidmap plugin to geoserver. But i'm hitting this url

http://localhost:8080/geoserver/topp/wms?service=AMS&version=1.1.0&request=GetMap&layers=topp:accidents_genPoint&styles=&bbox=73.666,18.401,73.98,18.744&width=468&height=512&srs=EPSG:4326&format=application/openlayers

and getting the following error as,

<ows:ExceptionReport xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ows="http://www.opengis.net/ows" version="1.0.0" xsi:schemaLocation="http://www.opengis.net/ows http://localhost:8080/geoserver/schemas/ows/1.0.0/owsExceptionReport.xsd">
<ows:Exception exceptionCode="NoApplicableCode">
ows:ExceptionText
java.lang.RuntimeException: No response: ( object = class org.geoserver.wms.map.RenderedImageMap ) No response: ( object = class org.geoserver.wms.map.RenderedImageMap )
/ows:ExceptionText
/ows:Exception
/ows:ExceptionReport

I try to google this error but don't find anything, for the setup i have used

1] Geoserver Binary 2.1.0
2] Acidmap plugin for linux i.e. AcidMaps_2.0_JNI_Linux.tar.gz
3] Ubuntu 12.04 LTS

Any help on this issue will be much appreciated.