Nginx doesn´t restart after installation of ISPConfig 3

[cyprus]

Okay here I am the last 3 days I was setting up a server from scratch with one focus getting ISPConfig running.

I used debian with bind & courier nginx as serversoftware thttpd for cgi implemented fastcgi and squirrelmail and walked a long way.
Everything worked fine and then I installed ISPConfig.
In the first moment everything seems to be okay. But I couldn´t call my server via browser got a "bad gateway".
I tried to restart nginx and got this:

root@v10300122146:~# /etc/init.d/nginx restart
Restarting nginx: nginx: [emerg] SSL_CTX_use_certificate_chain_file("/etc/nginx/cert.pem") failed (SSL: error:02001002:system library:fopen:No such file or directory error:20074002:BIO routines:FILE_CTRL:system lib error:140DC002:SSL routines:SSL_CTX_use_certificate_chain_file:system lib)
nginx: configuration file /etc/nginx/nginx.conf test failed

It looks like an SSL problem but there aren´t any *.pem files in my nginx folder. And I ain´t got no idea how to fix it.

Thanx for every hint

Cyprus