That makes base sound worse than it is. If you write:

#!/usr/bin/perl
use strict;
use warnings;
use base qw/Kjfnekjrn/;
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you get:

Base class package "Kjfnekjrn" is empty.
    (Perhaps you need to 'use' the module which defines that package f
+irst.)
 at tt.pl line 4
BEGIN failed--compilation aborted at tt.pl line 4.
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You're absolutely right that it isn't complaining that it couldn't find the file, but the error message is helpful and to the point, in my opinion.