[Skunkworks] KRA Uploading Macros File - Witholding Tax

Hello , I have been trying to upload the Excel Macros File onto KRA ITax Payments however i keep getting an error as below *Your Error Reference No. is :1447667370665* *Problem encountered in iTax, Please contact the KRA call center at below contact details and quote the above Error Reference No. for resolution.* Is this a compatibility error ? - I am using Excel 2013 however i have the saved the file as a *.XLS * Has anyone encountered this problem before ? Regards , CK