Crystal Reports Unable to view the reports

Message

   I have developed a web application using VS 2005 and developed some reports using CRYSTAL REPORTS XI and i have deployed the application on the server my server configuration is OS:Windows Server 2008 and iam using SQL Server 2008 as my database and IIS 7 iam getting the following error:

Error executing child request for ReportViewer.aspx.Error executing child
request for ReportViewer.aspx.

at System.Web.HttpServerUtility.ExecuteInternal(IHttpHandler handler,
TextWriter writer, Boolean preserveForm, Boolean setPreviousPage,
VirtualPath path, VirtualPath filePath, String physPath, Exception error,
String queryStringOverride) at System.Web.HttpServerUtility.Execute(String
path, TextWriter writer, Boolean preserveForm) at
System.Web.HttpServerUtility.Transfer(String path, Boolean preserveForm)
at System.Web.HttpServerUtility.Transfer(String path) at
PL_Reports_VMS_VmsReport.cmdGenRpt_Click(Object sender, EventArgs e) at
System.Web.UI.WebControls.LinkButton.OnClick(EventArgs e) at
System.Web.UI.WebControls.LinkButton.RaisePostBackEvent(String
eventArgument) at
System.Web.UI.WebControls.LinkButton.System.Web.UI.IPostBackEventHandler.Rai
sePostBackEvent(String
eventArgument) at
System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl,
String eventArgument) at
System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) at
System.Web.UI.Page.ProcessRequestMain(Boolean
includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

kindly help me with a solution

Thanks in advance
Ramakrishna Reddy