A few tips :)

• there is no "cwd" module, case matters
• You've got subs, fantastic, now make them take parameters :) don't hardcode filenames
• speaking of filehandles, you can also use open my $foo, '<', ..., you don't have to use globals like FH1
• error checking is for everyone, even you can use autodie, or better still use Path::Tiny
• readdir is not for you, its like making your own stone/axe, when you already have swiss army chainsaw ... use Path::Tiny and/or File::Find::Rule; examples can be found with find/rule and path tiny links
• long if/else @ARGV option scan is busy work :) use perl -s or even better use Getopt::Long which allows you to use lexical variables not just globals
• you've got unicode text but you're not telling perl you're using unicode, or your console, see utf8.pm, binmode, open.pm perlunitut: Unicode in Perl#I/O flow (the actual 5 minute tutorial)
• naming is important, calling a subroutine "gethtml" when its purpose is to "sethtml" is too "clever"
• Basic debugging checklist and brian's Guide to Solving Any Perl Problem ) ... On debugging, verify everything, talk to teddybear ... checklists and more, Re^3: A Beginner Needs Homework help