Hi Qazi Anis,
Here is my submit code,
XPathNavigator mainds = this.MainDataSource.CreateNavigator();
FileSubmitConnection dc = (FileSubmitConnection)DataConnections["Main submit"];
dc.FolderUrl = mainds.SelectSingleNode("/my:myFields/my:Header_Section/my:FCR_fldrUrl", NamespaceManager).Value;
dc.Execute();
During the first submit, i am computing the folder url and storing in a field of the form itself. So during the second submit i am getting that and assigning it. But the execute fails with the error "A value in the form may be used to specify the file name. If you know the value in the form that specifies the file name, revise it and try again. Otherwise, contact the author of the form template"