Mysql - unknown variable 'table_cache=64'
Version 5.1.3 "Renamed the table_cache system variable to table_open_cache. Any scripts that refer to table_cache should be updated to use the new name."  However, it did not become an error until years later, in 5.7.6.  Change to table_open_cache.

However, what does the line in my.cnf look like?  Sounds like there is something else wrong.  Change it to

table_open_cache = 200


(If you have a tiny machine, 64 might be better.  But in today's machines, a few hundred is a better value.)