New Post: Error When Attachment

I migrated my database and application from a server to another.

After the migration i do have an issue uploading attachment.  Appreciate someone can help .

System.Web.HttpUnhandledException (0x80004005): Exception of type 'System.Web.HttpUnhandledException' was thrown. ---> System.ArgumentOutOfRangeException: StartIndex cannot be less than zero.
Parameter name: startIndex
   at System.String.InternalSubStringWithChecks(Int32 startIndex, Int32 length, Boolean fAlwaysCopy)
   at BugNET.BLL.IssueAttachmentManager.<IsValidFile>b__2(String fileType)
   at System.Linq.Enumerable.WhereSelectArrayIterator`2.MoveNext()
   at System.Linq.Enumerable.Any[TSource](IEnumerable`1 source, Func`2 predicate)
   at BugNET.BLL.IssueAttachmentManager.IsValidFile(String fileName, String& inValidReason)
   at BugNET.Issues.IssueDetail.SaveIssue()
   at BugNET.Issues.IssueDetail.LnkDoneClick(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.RaisePostBackEvent(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)
   at System.Web.UI.Page.HandleError(Exception e)
   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
   at System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
   at System.Web.UI.Page.AsyncPageProcessRequestBeforeAsyncPointCancellableCallback(Object state)
   at System.Web.HttpContext.InvokeCancellableCallback(WaitCallback callback, Object state)
   at System.Web.UI.Page.AsyncPageBeginProcessRequest(HttpContext context, AsyncCallback callback, Object extraData)
   at ASP.issues_issuedetail_aspx.BeginProcessRequest(HttpContext