Examples, with explanation of wrong in comment. First talk:
print $hash; # he accompanied this by a dump of the hash, when in reality it would print the reference id
print ($a, $b, $c); # same thing as above, pretends it does a dump, when the reality is wildly different
He does these repeatedly in his second talk:
$arg1, $arg2 = @_; # assigns the length of @_ to $arg2, instead of unpacking args. only the newest of newbies would get this wrong
if(ref $arg1 eq 'HASH') print $arg1{'key'}; # perl does not have block-less pre-fixed ifs
else print $arg1; # same with this, entirely nonsense
The entire style of his code (paren-usage, quoted hash keys) also smells of code copied from bad (w3schools) perl tutorials.
You're not talking about a small typo, are you?
Can you point to the wrong examples/slides?