I'm trying to add a release to the artist "Reste von Gestern" (http://musicbrainz.org/artist/4db92640-c27e-49cd-88db-f3ab271d83e7), but whenever I try to fill in the 1st tab, I get this error:

"Warning: There were one or more errors, please check the following fields: "
... and nothing to indicate where the problem lies. No field is highlighted in any way, and I can't see the error.

I filled out these fields: title ("Die Reste von Gestern"), artist ("Reste von Gestern"), type, status, date, country, packaging, and comment.
I removed the "label" row via the red X, as this is self-released.

My mb username for future reference: antoneeo

Thanks for your help!
Antonio