cannot upload image (audio and other ok). why?

[akulee]

first step ok.. "1 uploads were successful" but when i click continue, no image display and when i set the album, and click next, i've got this message "The previous file could not be placed".. my folder permission is 777. help me plzz, i'm new into this... ?

[Joachim Müller]

http://coppermine-gallery.net/demo/cpg14x/docs/index.htm#upload_trouble