Often, the method for using a control requires you to create an object reference to the control. Assuming that you have registered the control on a computer the typical syntax, such as ADO would use, would be:
Set oObject = Server.CreateObject("ObjectName.ClassName")
In the case of XLSConverterX, please use "XLSConverterX" as the Object name and XLSConverterXCtrl as the Class name. For example:
Set oObject = Server.CreateObject("XLSConverterX.XLSConverterXCtrl")