Here is the relevant chunk from perldiag, in case you didn't think/know to look there:

Use of inherited AUTOLOAD for non-method %s() is deprecated

           (D deprecated) As an (ahem) accidental feature,
           "AUTOLOAD" subroutines are looked up as methods (using
           the "@ISA" hierarchy) even when the subroutines to be
           autoloaded were called as plain functions (e.g.
           "Foo::bar()"), not as methods (e.g. "Foo->bar()" or
           "$obj->bar()").

           This bug will be rectified in future by using method
           lookup only for methods' "AUTOLOAD"s.  However, there
           is a significant base of existing code that may be
           using the old behavior.  So, as an interim step, Perl
           currently issues an optional warning when non-methods
           use inherited "AUTOLOAD"s.

           The simple rule is:  Inheritance will not work when
           autoloading non-methods.  The simple fix for old code
           is:  In any module that used to depend on inheriting
           "AUTOLOAD" for non-methods from a base class named
           "BaseClass", execute "*AUTOLOAD = \&BaseClass::AUTOLOAD"
           during startup.

           In code that currently says "use AutoLoader; @ISA =
           qw(AutoLoader);" you should remove AutoLoader from
           @ISA and change "use AutoLoader;" to "use AutoLoader
           'AUTOLOAD';".

I didn't take the time/effort to read it and fully understand it, but I hope it helps nonetheless.