I have the same problem with the series Shark. http://thetvdb.com/?tab=series&id=79388&lid=13 and Sonarr keeps complainting about There Was An Error Searching For ‘Shark’.
If the series title contains non-alphanumeric characters try removing them, otherwise try your search again later.
Can I manually add this series? Because I get the same when I try to import the series from Disk…
Thanks in advance!