Advanced Lesson Search Issues

I'm having trouble effectively using the Advanced Lesson Search (http://chinesepod.com/search) to find older lessons.  In particular, I would like to be able to get all lessons related to a particular topic (e.g. "business") or function (e.g. "ordering food").  However, if I just select a topic or function from the drop-down lists and click "Go", no lessons are returned.  It appears that only searching by keyword and category are working right now.

The only way I found to get all lessons related to a topic is to already know one of lessons, go to that lesson page and click on the particular topic name link.  This returns a list of lessons matching that topic.  However, I usually don't know a related lesson before hand to do this (that's why I'm searching in the first place).

Other issues I found with the Advanced Lesson Search: 

• selecting a topic or function that contains a "/" and clicking "Go" yields a 404 error page
  
• topic and function drop-down lists are not sorted alphabetically

My wish list for the Advanced Lesson Search would include:

• cleaning up the topics and functions - there appears to be some redundancies in the lists
• ability to search by multiple categories - for example: "give me all Newbie AND Elementary lessons dealing with numbers"