I need a handler plug-in?

Ok, if this isn't on the right board, I'm sorry. I'm new here, and I just found this board today.

I got this katana II back in December [1st, I believe]. I went onto Mbuzzy, and I made some of my own ringtones, and sent them to my phone. My first batch was great. They all came up and work fine. I then go to make another batch, and it says that I need a handler to make them work [in plain english]. And I seem to recall something about a plug-in needed when I downloaded them.

It's been 2 months. >_>; I tried making a few last night, and it still says I need the handler. [Duh.]

All right. What exactly IS a handler? How do you get one [in detail, please]? And does it cost anything? Because I would really like for these ringtones to work.

Can someone help me out?
Thanks in advance.