Office 2010 attachment not working in SUS PO

Dear Experts,

I am creating a PO with header attachment and when the PO is sent to SUS vendor the attachment ie any office 2010 document with extn.docx .pptx etc is not getting opened but the attachment with extn .doc .ppt is working fine.Kindly guide me how and where i can check for the solution.

Thanks in advance

Regards

Arun.K.P