You need an interpolating quote operator: 
my $find_button = $mech->xpath(qq{//*[\@id="$Pager"]}, single => 1 );

[download]
Edit: forgot to escape "@"
Sorry if my advice was wrong.

In reply to Re: WWW::Mechanize::Firefox Navigate Issue ! by aitap
in thread WWW::Mechanize::Firefox Navigate Issue ! by Matt™

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