You're confusing the heck out of the tokenizer -- it gets to the _ in ${_} and thinks that you want to terminate the regex. Use a \ to get perl to understand what you mean. An example:

$_ = "o";
print "foo\n" if "foo" =~ m _${_}_;  # Dies
print "foo\n" if "foo" =~ s _${\_}_; # Happy
[download]

perl -pe '"I lo*`+$^X$\"$]!$/"=~m%(.*)%s;$_=$1;y^`+*^e v^#$&V"+@( NO CARRIER'