As you followed my advice I could hardly not try and help!

Anyway changing

  (\W*?) # this shouldn't be necessary since whitespace should have be
+en slurped on previous line but this shouldn't hurt either
[download]

... to ...

          (\s*?) # this shouldn't be necessary since whitespace should
+ have been slurped on previous line but this shouldn't hurt either
[download]

fixes it. Horrah. $1 printed 'isitvalid("templatefile.html")' when I tested it

Anyway \s is a more standard way of matching whitespace, so I guess you could get milage out of changing all your instances of \W*?, which are probably matching more than you expect. Case in point.

my $test = '{}[]£$%';
my $match = ($test =~ m/(\W*)/)[0];
print $match;

__OUTPUT__
{}[]£$%
[download]