"... 'Modification of non-creatable array value attempted' ..."

I doubt that has anything to do with VirtualBox. I typically see that when I've used an expression for the array index which evaluates to an invalid value for the index.

$ perl -e 'my @x; $x[0] = 1'

$ perl -e 'my @x; $x[-1] = 1'
Modification of non-creatable array value attempted ...
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You can also search for that error in perldiag.

I'd look for something like '$ary[$i-$n]'. Also check for off-by-one errors: as an entirely contrived example, perhaps you have 'for my $i (0 .. $x)', which should really be 'for my $i (1 .. $x)'.