upps..

thank you for your help, it works!

I was just thinking:

DROP Index table_name.index_name

also must be:

ALTER INDEX index_name ON table_name.index_name REBUILD;

but I was wrong...

create table testen

(iid int not null, strasse varchar(50), plz varchar(10))

insert testen

values (3,'gutes 12','1123')

create nonclustered index strasse on testen(strasse)

sp_helpindex testen

ALTER INDEX strasse ON testen.strasse

REBUILD; => here I get an error saying:...