Strange error in log file

Hi,

I reviewed SSRS log file and found an error entry (see below). What causes the problem?

webserver!ReportServer_0-25!2684!09/22/2011-09:09:40:: i INFO: Processed report. Report='/StartHere/MyCoolReport', Stream=''
rshost!rshost!a28!09/22/2011-09:09:40:: e ERROR: WriteCallback(): failed to write in write callback.
rshost!rshost!a28!09/22/2011-09:09:40:: e ERROR: Failed with win32 error 0x0016, pipeline=0x00000000006EEFA0.
rshost!rshost!2684!09/22/2011-09:09:40:: e ERROR: HttPipelineCallback::SendEntityBody(): failed async writing entity body.
rshost!rshost!2684!09/22/2011-09:09:40:: e ERROR: Failed with win32 error 0x0016, pipeline=0x00000000006EEFA0.
httpruntime!ReportServer_0-25!2684!09/22/2011-09:09:40:: e ERROR: Failed in BaseWorkerRequest::SendHttpResponse(bool), exception=System.Runtime.InteropServices.COMException (0x80070016): The device does not recognize the command. (Exception from HRESULT: 0x80070016)
   at Microsoft.ReportingServices.HostingInterfaces.IRsHttpPipeline.SendEntityBody(Void* chunks, UInt16 chunkCount, Boolean finalWrite, Boolean closeConn)
   at ReportingServicesHttpRuntime.BaseWorkerRequest.SendHttpResponse(Boolean finalFlush)
library!ReportServer_0-25!2684!09/22/2011-09:09:40:: e ERROR: Throwing Microsoft.ReportingServices.Diagnostics.Utilities.ReportServerHttpRuntimeInternalException: RsWorkerRequest::FlushResponse., Microsoft.ReportingServices.Diagnostics.Utilities.ReportServerHttpRuntimeInternalException: An internal or system error occurred in the HTTP Runtime object for application domain ReportServer_MSSQLSERVER_0-25-129611683038432174.  ---> System.Runtime.InteropServices.COMException (0x80070016): The device does not recognize the command. (Exception from HRESULT: 0x80070016)
   at ReportingServicesHttpRuntime.BaseWorkerRequest.SendHttpResponse(Boolean finalFlush)
   at ReportingServicesHttpRuntime.RsWorkerRequest.FlushResponse(Boolean finalFlush)
   --- End of inner exception stack trace ---;

Thanks.