sub Testing {
    my ($VAR5,$VAR6,$VAR7,$VAR8) = @{$_[0]}; 
    print "Var5: $VAR5\tVar6:$VAR6\tVar7: $VAR7\tVar8: $VAR8\n";
}
[download]

$_[0] is the first element of the array @_

$_ is something completely different

> main::Testing() called too early to check prototype at C:\temp\arr_refernce.pl line 11.

Do

sub Testing {

not

sub Testing (){

if you want to pass arguments.