Looks like the admins there didn't do a dry run on a backup database before converting - there are all sorts of parsing errors popping up in the posts. Can I fix these problems ? Maybe. Will I fix them ? Nuh-uh...
However, here is a MySQL tidbit for you Elmers, to get you started.
update [some_table] set [some_field] = replace([some_field],'[problem_characters]','[corrected_characters]');
One of your problems is this == /' appearing in quoted text - seems the old forum stuck escape codes in place that the new forum doesn't need. You can look up escape codes and figure that part out on your own. Have fun, Elmers !