System error

error:  The 'comp_source' parameter to HTML::Mason::Interp::make_component was an 'undef', which is not one of the allowed types: scalar
context: 
... 
375:  my $article = $is[0] =~ /^[aeiou]/i ? 'an' : 'a';
376: 
377:  my $called = _get_called(1);
378: 
379:  $options->{on_fail}->
380:  ( "$id to $called was $article '@is', which " .
381:  "is not one of the allowed types: @allowed\n" );
382:  }
383:  }
... 
code stack:  /usr/local/lib/perl5/site_perl/5.8.0/Params/Validate.pm:379
/usr/local/lib/perl5/site_perl/5.8.0/Params/Validate.pm:258
/usr/local/lib/perl5/site_perl/5.8.0/HTML/Mason/Interp.pm:352
/usr/www/docs/mei/dhandler:39
/usr/www/docs/mei/autohandler:7