Missing file themes/slash/topbg.jpg

The release from October 14th of the Slash theme generates on my sites an "Missing file" error (themes/slash/topbg.jpg).

However, the sites, where Drupal is installed in the root (server-root/themes/slash) still look OK after purging the browser's cache, while those with Drupal installed in a subdirectory (server-root/drupal/themes/slash) look broken (no coloring of the header). And even this occurs erratic since the header reappears if I change from "slash" to "slash_black"; also, after changing from "slash" to "slash_black", the mentioned "Missing file" error disappears, also. When switching back from "slash_black" to "slash", the "Missing file" warning reappears in the logs.

Also, the "admin" section looks a bit funny funny as it seems no longer to be themed (Administration theme under admin/settings/admin is set to "System default"; switching to something like slash_black does not give the theming back.

I'm using the "Slash" themes for several months and they never gave me any trouble; I have no idea what is going wrong.

I tried to overwrite the files in the server (/var/www/site/portal/themes/slash) several times which did not change the behaviour.

Any ideas?

Thanks & greetings, -asb