It looks like you're using the Performance Monitoring Supplemental Pack.
"Failed to process plugin: xcp-rrdd-xenpm" looks like a known issue. (The problem is that xcp-rrdd doesn't cope with metrics payloads greater than 16KiB.)
This will not affect operation at all -- it merely means that you won't see any metrics about the time your server's CPUs spend in C- and P-states.
If my guess about the cause of the issue is correct, and you are feeling brave, you could attempt to fix this by applying a XenServer hotfix (XS61E017, available from http://support.citrix.com/article/CTX137168) to your XCP host. But I don't know the details on how to do this -- I'm sure someone else on this list could help you if you want to try this.