Had problems with iBroser as wellbut solved the following way:
Made sure the extension I was trying to use was entered into the "Allowed extensions for upload" in the preferences/general prefs setting.
Then I found there was a permission problems with my tinymce temp dir. After setting the correct permissions for (Chmod 777, it was set to 755 but didn't work): admin/tinymce/jscripts/tiny_mce/plugins/ibrowser/temp/
After this ibroser could upload and move the file to the correct folder for general use. No more errors.
hope this helps, if anyone has any clever info to add please do
My experience with vivvo is that you have to check every option in the preferences and read the error messages. So far most of my problems where permissions problems.