I have this warning
(Last new path : none yet (odd, check syntax!))
in red after I try to fuzzing a file. I have no idea why it happens and I googled with no answers.
My command is like:
afl-fuzz -i testcases/ -o findings/ tcpdump-4.6.2/tcpdump -nr @@
It usually means that your command line doesn't actually read the file. Try running it without afl-fuzz, substituting @@ with a path to a file from the testcases directory. Hopefully tcpdump's message will tell you what is wrong.
In the future, you might get more attention on the afl-users mailing list. Try that if you're not getting any help on SO.