Testing attachment for Bugbatter: fails

Tried to attach test.txt, got the message

 Only files with the following extensions are allowed: gif, jpg, jpeg, png, bmp, txt, avi, wmv, asf, flv, dat, rm, rmvb, mov, mpeg, avi, wmv, wma, mp3, ra . Please select a valid file.

I'm quite sure it is a .txt file :-)

Trying a .png file. No dice either