I think it's time to upgrade!
This product is so old I don't even have a copy of it and I can't run vB 3 anymore, so I'm not sure I can get this working for you, but I'll give it a try here.
Open textarea.php and look for these:
Near the top
dir="<?php echo vB_Template_Runtime::fetchStyleVar('textdirection' ); ?>"
lang="<?php echo vB_Template_Runtime::fetchStyleVar('languagecode') ; ?>"
charset=<?php echo vB_Template_Runtime::fetchStyleVar('charset'); ?>"
Near the bottom
dir="<?php echo vB_Template_Runtime::fetchStyleVar('textdirection' ); ?>"
Now just edit them out and see what happens. They should default to the right values.