I'm raising a Selnium-server (the jar), and getting this exception without trying to talk to the server. What can be the cause? The errors keep coming in once every 2 seconds. Could this be some leftover from a previous Selenium run?

C:\Foo>java -jar ..\..\..\..\lib\Selenium\selenium-server.jar
14:53:30.141 INFO - Java: Sun Microsystems Inc. 14.2-b01
14:53:30.142 INFO - OS: Windows Server 2008 6.1 amd64
14:53:30.149 INFO - v1.0.1 [2696], with Core v@VERSION@ [@REVISION@]
14:53:30.209 INFO - Version Jetty/5.1.x
14:53:30.210 INFO - Started HttpContext[/selenium-server/driver,/selenium-server/driver]
14:53:30.211 INFO - Started HttpContext[/selenium-server,/selenium-server]
14:53:30.211 INFO - Started HttpContext[/,/]
14:53:30.217 INFO - Started SocketListener on 0.0.0.0:4444
14:53:30.218 INFO - Started org.mortbay.jetty.Server@2747ee05
14:53:31.729 INFO - Checking Resource aliases
14:53:31.735 WARN - POST /selenium-server/driver/?seleniumStart=true&localFrameAddress=top&seleniumWindowName=
&uniqueId=sel_27224&sessionId=1f2385b8bae24f6fb79816753de7cd69&counterToMakeURsUniqueAndSoStopPageCachingInThe
Browser=1255006411692&sequenceNumber=268 HTTP/1.1
java.lang.RuntimeException: sessionId 1f2385b8bae24f6fb79816753de7cd69 doesn't exist; perhaps this session was
 already stopped?
        at org.openqa.selenium.server.FrameGroupCommandQueueSet.getQueueSet(FrameGroupCommandQueueSet.java:218
)
        at org.openqa.selenium.server.SeleniumDriverResourceHandler.handleBrowserResponse(SeleniumDriverResour
ceHandler.java:159)
        at org.openqa.selenium.server.SeleniumDriverResourceHandler.handle(SeleniumDriverResourceHandler.java:
127)
        at org.mortbay.http.HttpContext.handle(HttpContext.java:1530)
        at org.mortbay.http.HttpContext.handle(HttpContext.java:1482)
        at org.mortbay.http.HttpServer.service(HttpServer.java:909)
        at org.mortbay.http.HttpConnection.service(HttpConnection.java:820)
        at org.mortbay.http.HttpConnection.handleNext(HttpConnection.java:986)
        at org.mortbay.http.HttpConnection.handle(HttpConnection.java:837)
        at org.mortbay.http.SocketListener.handleConnection(SocketListener.java:245)
        at org.mortbay.util.ThreadedServer.handle(ThreadedServer.java:357)
        at org.mortbay.util.ThreadPool$PoolThread.run(ThreadPool.java:534)