When a user clicks a link to download a file it produces this error in the site log:

AssemblyVersion: 04.04.00
PortalID: 0
PortalName: The Department of Medicine, John A. Burns School of Medicine at the University of Hawaii
UserID: 1
UserName: host
ActiveTabID: 80
ActiveTabName: Clinical Faculty
RawURL: /LinkClick.aspx?fileticket=ZEPDGs571VM%3d&tabid=80&mid=432&forcedownload=true
AbsoluteURL: /LinkClick.aspx
AbsoluteURLReferrer: http://www.uhmed.org/Home/Faculty/ClinicalFaculty/tabid/80/Default.aspx
UserAgent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0; .NET CLR 1.1.4322)
DefaultDataProvider: DotNetNuke.Data.SqlDataProvider, DotNetNuke.SqlDataProvider
ExceptionGUID: a5c5a1ea-e740-4a5b-8a12-4b80d262b30f
InnerException: Unhandled Error:
FileName:
FileLineNumber: 0
FileColumnNumber: 0
Method: System.Web.HttpResponse.AppendHeader
StackTrace:
Message: System.Exception: Unhandled Error: ---> System.Web.HttpException: Server cannot append header after HTTP headers have been sent.at System.Web.HttpResponse.AppendHeader(String name, String value)at DotNetNuke.HttpModules.Compression.CompressingFilter.WriteHeaders()at DotNetNuke.HttpModules.Compression.GZipFilter.Write(Byte[] buffer, Int32 offset, Int32 count)at DotNetNuke.HttpModules.Compression.WhitespaceFilter.Write(Byte[] buffer, Int32 offset, Int32 count)at System.Web.HttpWriter.Filter(Boolean finalFiltering)at System.Web.HttpResponse.Flush(Boolean finalFlush)at System.Web.HttpResponse.Flush()at DotNetNuke.Common.Utilities.FileSystemUtils.DownloadFile(Int32 PortalId, Int32 FileId, Boolean ClientCache, Boolean ForceDownload)at DotNetNuke.Services.FileSystem.FileServerHandler.ProcessRequest(HttpContext context)at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)--- End of inner exception stack trace ---

Any help will be much appreciated. Thanks.

Could anyone point me in the right direction as to how I could solve this problem or where I could go to get information about the problem?  Also, I am not sure how to turn off compression to test to see if this is the problem.