On average, a TaskLog like this one does not provide you with actual information about the error. It just complains, but you'll have to look for a decent explanation elsewhere. For example if a Reload Task fails because of some error in the load script, the TaskLog will contain a message about a reload failure with all sorts of additional useless info. But for a real pointer to the erroneous statement, you'll have to check the Document Log.
Go to C:\ProgramData\QlikTech\DistributionService\1\Log\, open the daily sub-directory, look for the task log folder and open the DocumentLog.txt file in that folder.
You'll have to enable creation of a log file in your document first (see Dekstop:Settings->Document Properties...->General->Generate Logfile), otherwise there won't be any DocumentLog.