Your confusion may be coming from the order in which @ and [3] are being handled. @ first converts $fldref from an array reference into an array. Then it lets you use normal array element syntax, @$fldref[3], to access its elements. In other words, @$fldref[3] is equivalent to $fldref->[3].

You might be able to see this more clearly if we replace $fldref->[3] with a variable, like this:

my $aVars=  [
    ["\$a", "Tarina Babarista, pienest{ elefantista"],
    ["\$s", "(26'34); orkestroitu"],
    ["\$d", "Poulenc, Francis"],
    ["\$g", "Brunhoff, Jean de "],
    ["\$h", "P|ysti, Lasse"],
    ["\$j", "Fran*8aix, Jean"],
  ];

my $fldref= [ 500, 0, 0, $aVars ];
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$fldref->[3] is $aVars, a reference to an array and not the dereferenced array, @$aVars. So when you loop on foreach (@$fldref[3]) you are really looping on foreach($fldref->[3]) which is just a loop over the single element $aVars. That is why you dump only once inside the foreach loop and see the $aVars array as a whole when you dump it rather than the individual elements of $aVars, each dumped separately.

If you want to loop on the contents of $fldref->[3] you have to dereference it yet again and do @{$fldref->[3]} or @{@fldref[3]}. This works as expected:

foreach my $tmp (@{$fldref->[3]}) {
  print "$tmp: <@$tmp>\n";
}

#outputs
ARRAY(0x814ec28) <$a Tarina Babarista, pienest{ elefantista>
ARRAY(0x81e652c) <$s (26'34); orkestroitu>
ARRAY(0x81e64fc) <$d Poulenc, Francis>
ARRAY(0x81e5a4c) <$g Brunhoff, Jean de >
ARRAY(0x81f236c) <$h P|ysti, Lasse>
ARRAY(0x81f239c) <$j Fran*8aix, Jean>
[download]

Hope that helps, beth