In the VB code you pass two parameters to the RLVersion(), you should do the same in Perl. You just need to tell Win32::OLE that you want that parameter passed by reference. Something like this might help:

use Win32::OLE::Variant;
my $y = Variant(VT_BSTR || VT_BYREF, "");
$RL->RLVersion(1, $y);
print $y;
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I think something like this should work.