Resource Cannot be displayed with xml resource render

Hello Experts,

we have created KM Navigation iview and setted the property "Path to Initially Displayed Folder =/documents/dealer/news" this folder path contains the XML news,PDF's ,Excel file.

When we see the iview with an end User perspective,XML News are displaying properly but for PDF's and Excell file getting the error as

"Resource cannot be displayed with XMLResourceRenderer".

When we have checked under system admin-->System Configuration-->monitoring-->knowledge management-->component monitor,we are getting the below Services warning message

version : EP7.0 SP20 .

Please help me regarding this issue.

Best Regards,

Kiran B