If you get this error:

Warning: fread(): Length parameter must be greater than 0. in /home/XXXXX/public_html/system/core/core.template.php on line 1814

when viewing a template, then it is necessary to clear your caches by going to Admin -> System -> Utilities -> Clear Cached Log Files.  The error indicates that a cache file with zero data in it is trying to be read.  This may mean that a cached file is corrupted, so clearing the cache should fix the problem.