Plugin appends /?/ and / to urls and language switches.

I’m currently working on a bilingual site with Japanese as the primary language. When I switch to English, all is fine and /?lang=en is properly appended to the URL. However, from there, if I try to click the navigation links on the nav bar, it appends /?/ to the base site and defaults back to Japanese. I’ve checked it with the proper suffix (/?lang=en) and it is fine…but where is this single lone question mark and back slash coming from.

In the same situation, if you click on the site logo to go home, it appends /?lang=en properly, but adds a single back slash to the end (?lang=en/), thereby making it default back to Japanese.

If anyone knows the answer, please help!!

Here’s the site:
http://www.select-tokyo.com

http://wordpress.org/plugins/qtranslate/