You're receiving "Error saving the CertificateRequestInitiate...Request Skipped; letter template not found" when requesting a certificate for a customer from your ERP.
In CertCapture, there must be a letter template with the title "STANDARD_REQUEST"
Go to Request->Email Templates/Cover Letters and choose the one you wish to use for the request and click Edit on the right
Change the title, it is case sensitive, to "STANDARD_REQUEST"
Click Update Cover Letter Template