Thanks for your reply: I guess I know what you are talking about, I'm just wondering why Netscape knows the filesize when I manually download an emusic MP3 (can be seen in the progress bar).

Anyway, my current workaround is the following: emusic samples with 128Kb/sec. Furthermore, the expected length of a song is given in min:sec on the refferring page. So I extract the duration of each song, calculate the expected file size and check if my downloaded file fits approximately within this range. It's a hack and only recognizes gross errors.