ERROR:java.io.UnsupportedEncodingException:

I use websphere on window

------------request------------------
POST http://xx.xxx.xxxx.xx/awdServer/console ... LOGOFFUSER HTTP/1.1
Accept-Language: en-us
Accept-Encoding: gzip, deflate
Connection: Keep-Alive
Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-shockwave-flash, application/x-silverlight, application/x-ms-application, application/x-ms-xbap, application/vnd.ms-xpsdocument, application/xaml+xml, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*
Content-Type: application/x-www-form-urlencoded
Pragma: no-cache
User-Agent: Jakarta Commons-HttpClient/3.1
Host: 10.193.247.95
Content-Length: 0

and response it seem ok but I found something in error log in soap UI as below
------------error log------------------
Tue Oct 26 16:53:02 ICT 2010:ERROR:java.io.UnsupportedEncodingException:
java.io.UnsupportedEncodingException:
at java.lang.StringCoding.decode(Unknown Source)
at java.lang.String.<init>(Unknown Source)
at com.eviware.soapui.impl.wsdl.submit.transports.http.SinglePartHttpResponse.<init>(SinglePartHttpResponse.java:71)
at com.eviware.soapui.impl.wsdl.submit.transports.http.HttpClientRequestTransport.createDefaultResponse(HttpClientRequestTransport.java:236)
at com.eviware.soapui.impl.wsdl.submit.transports.http.HttpClientRequestTransport.sendRequest(HttpClientRequestTransport.java:192)
at com.eviware.soapui.impl.wsdl.WsdlSubmit.run(WsdlSubmit.java:122)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)


Someone suggest me what is wrong ?