Error installing GWDR on SLES15

Hello Members,
 
I tried to install gwdr-18.1 downloaded from customer center on a SLE15 or SLE15sp1.
 
Whether I install via install.sh or via direct rpm-install I got an error:
 
rpm -ivh gwdr-18.1.0.rpm
Preparing... ################################# [100%]
Updating / installing...
1:gwdr-18.1.0-1 ################################# [100%]
/var/tmp/rpm-tmp.PaE4rS: line 2: ./install: No such file or directory
 
 
Does anybody has an idea what's going wrong?
 
Thanks for help,
 
Michael