OK, I uploaded it with the same name (Classical_Dark for Ipod video), and it is now there, replaced the old one. The download count and voting results are reset however. Not shure if this is a feature or a bug.
While doing the email-verification I got the following error on top on the page:
Warning: rename(../private/themes/320x240/classical_dark/Classical_Dark.zip,/home/themes/www//themes/320x240/classical_dark/Classical_Dark.zip) [function.rename]: No such file or directory in /home/themes/private/themesite.class.php on line 380
Hope this may be of any help to the maintainers.
Thanks to all answerers!