ExecuteMacro Error



Hi,Can any one plz help me with the exception ,while executing Macro

Execute macro : Unable to cast COM object of type ‘System._ComObject’ to interface type ‘Microsoft.Office.Interop.Excel.Workbook’. This operation failed because the QueryInterface call on the COM component for the interface with IID ‘{000208DA-0000-0000-C000-000000000046}’ failed due to the following error: The application called an interface that was marshalled for a different thread. (Exception from HRESULT: 0x8001010E (RPC_E_WRONG_THREAD)).