If I use the here doc, how do I use this in conjunction with xargs? I thought that required it to be a one-liner?

find /home/site/htdocs -name "*.html" | xargs -n 1 perl -pi <<'PRG_END
+'
s|<!--#include virtual="/ssi/footer.txt"-->|<?php include(\$_SERVER['D
+OCUMENT_ROOT'].'/ssi/footer.txt'); ?>|g;
PRG_END
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Thows errors like this:

Can't open perl script "s|<!--#include": No such file or directory.
Use -S to search $PATH for it.
Can't open perl script "virtual=/ssi/edfooter.txt-->|<?php": No such f
+ile or directory.
Use -S to search $PATH for it.
Can't open perl script "include($_SERVER[DOCUMENT_ROOT]./ssi/edfooter.
+txt);": No such file or directory.
Use -S to search $PATH for it.
Can't open perl script "?>|g;": No such file or directory.
Use -S to search $PATH for it.
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