while ($i < @OIDs) {
    my $varname = "varbindhash$i";
    $$varname{'OID'} = $OIDs[$i];
    ...
}

##</code><code>##

my @varbindhashes = ();
...
while ($i < @OIDs) {
    $varbindhashes[$i]->{'OID'} = $OIDs[$i];
    ...
}