To fix your error with the two different binds, just make the parameter list {args} since you don't use any of them anyway.
There are two errors: $topic isn't set, and $channel isn't set. Well it looks like the $channel var is supposed to be $ccdrift_channel instead, so that's easy to fix. Topic is also very easy, there is a command called 'topic' which retrieves it. So right after your "global" line, put this:
set topic [topic $ccdrift_channel]
and all should be well. (You might also want to change the if {$topic != $html} { to read instead, if {[string compare $topic $html]} { )