Can't download ringtones because "the file type is not supported"

Ok, so normally I go to www.myxertones.com and download all of my ringtones from there. For those of you who arent familiar with myxertones.com, you go there, choose a song, and send it to your phone via a text message. From the text you click on the link and it brings you to a webpage where you download the song and save it to your phone or memory card. I have done this forever, and when I first got this phone it was working fine. Yesterday I sent myself a few ringtones and when I try to download it, I get an error message saying "This file will not be downloaded because the locked file type is not supported on this device." I never deleted anything or changed any settings so I have no idea what happened. I tried restarting my phone, taking the battery out, and checking the settings. As far as I can see everything is fine. I tried to download on both Internet Explorer and Opera Mobile. Can anyone help please? I need ringtones!    

i'm not exactly sure. i think they are .mp3's (thats what i always figured most music was downloaded off the internet). but after i download them, my phone is playing them through windows media player and automatically saving them as .wma's. how would i find out if they are originaly mp3's?