Description of problem: If create some tags with ctags, and then vim -t somesymbolthatdoesntexist vim prints the warning message.. E257: cstag: tag not found which should be 'ctags'
No, this isn't a typo. vim supports cscope which uses the cstag command. vim searches cscope database(s) first, followed by tag file(s) if cscope did not return any matches. Set vim's csto variable to 1 if you'd like vim to search in the tag file(s) first: :set csto=1