Welcome to AG Southpaw.
Both of those issues (rat trap and curtain) are bugs that the developers released a patch for.
http://files.filefront.com/Secret+Fi.../fileinfo.html
If you install that, you should be able to get past the curtain part. Keep in mind that it enhances the ending a bit. So if you want to save a game close to the end, play it with the patch to see the enhanced ending then remove the patch and watch the old ending, you could.