What version of Hoster are you running?
A new "compressed" .WAV file hit the scene a few years ago. It violated every rule for WAV audio files, which had ALWAYS contained UNCOMPRESSED data.
If you have MTU's Songverter, try converting several of your .wav files that won't open as Instabutton files. Convert them to .WMA format and then try to open them as Instabutton files.
If that doesn't work, we need to get one of your "bad" .wav files to study what is wrong. If this needs to be done, click the Chat link at the top (header) of any MTU.com web page, and select Support. If no one is on-line, you will get a form to submit. Ask Bryan; "Please arrange to come into my computer to upload a bad .wav file that won't work in Instabuttons. Dave told me to do this."
