At the web site https://docstore.mik.ua/orelly/perl4/perlnut/ch23_05.htm there is a description of Win32::OLE::Const.
The 2nd paragraph is
You can either import the constants directly into your namespace as subs that return the constant value, or you can have them returned as a hash reference with the constant name as the key and its value as the value. Here's an example of the former:
use Win32::OLE::Const ("Microsoft Excel");
print "xlExcel5 = ", xlExcel5, "\n";
This produces something like:
xlExcel5 = 39

I had been using this successfully for some time.
However, in October 2012 I started getting No type library matching error messages for the 1st Win32::OLE line above.
I asked the Perl Monks about this and got a number of replies.
One of these was to have the line
use Win32::OLE::Const "Microsoft Excel .* Object Library";
This worked but now has started to fail with the No type library matching error message
Another suggestion in 2012 was to have the following 
use Win32::OLE;
use Win32::OLE::Const;
my $Excel = Win32::OLE->new('Excel.Application', 'Quit');
my $xlcon = Win32::OLE::Const->Load($Excel);
foreach $key (sort {$a cmp $b} keys %$xlcon) {
    print "$key value $xlcon->{$key}\n";
}

[download]
This works, which is good.
However, I wondered if any Monk knew:
1. Why the row suddenly started giving these errors – as far as I can tell no changes have been made to the system;
2. Why the same version of Perl is continuing to work without any issues on another system;
3. How I could prevent the errors – (I appreciate that I probably can use the working Perl however I do not want to do that only to find that this suddenly stops working).

In reply to Excel Const - No type library matching error message by merrymonk

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