Please help a newbie

i have downloaded supernatural s2 e10 and the dresden files.
they are showing up as avi fb files????????
can anyone tell me what fb is and how to open or convert it
i am using convertxtodvd with no probs 'till now
thanks

erm ... did you get them from here ?
all files here are just straight .avi

copy and paste the complete name and extension, that will give us a better idea.
sometimes a file might look like this: loopyloop.avi.bc

the bc part is for bitcomet and is added to the extension until the download is
complete

more details please, inc the name of your p2p client

thanks guys
i redownloaded and the files work fine now