functioning as a class, but that package doesn't define that particular
method, nor does any of its base classes. See L<perlobj>.
+=item Can't locate PerlIO%s
+
+(F) You tried to use in open() a PerlIO layer that does not exist,
+e.g. open(FH, ">:nosuchlayer", "somefile").
+
=item (perhaps you forgot to load "%s"?)
(F) This is an educated guess made in conjunction with the message