PDF Error being generated

When i am creating a pdf report the system is generating an error. Any one else getting this and how to fix it.
Any Help would be greatly appreciated

XML Parsing Error: not well-formed
Location: http://www.zindelasolutions.com/piwik/index.php?module=API&action=index&idSite=3&period=month&date=2015-11-01&updated=1&token_auth=xxxx&method=ScheduledReports.generateReport&idReport=6&outputType=3&language=en
Line Number 1, Column 9:%PDF-1.7

It is working for me now, maybe it was a temporary server issue?

btw I’ve removed token_auth from your post, you should change your password to have a different token in case someone got it