You will have to get the SD card out and edit the sudoers file in an other computer. Restore the file to what it was.
Every time you do something like this ALWAYS make a copy your original file under another name eg. myfile.bak. This way you can easily restore to when it was working and then you can try again!
Thanks for the Reply.
I´ve tried your way earlier, but I can´t download or edit the sudors file, because I´ve no permisson to do that…
Vincent has the solution.
You need to mount the SD card on some other machine where sudo is not broken and edit the sudoers from there. You will still need to be root (i.e. sudo) even on that other machine where you mount the SD card to to access the file.
And in the future, ALWAYS edit sudoers using visudo. If there is something wrong with what you changed, it will reject the change instead of breaking sudo on your machine.
If the SD card is mounted to /mnt/sdcard then the command would be
sudo visudo -f /mnt/sdcard/etc/sudoersOnce in a while, I come up with 
When I use my MAC, connect with cyberduck, Ißm not able to download that file, because of missing permissions…
How can I solve that problem?
Get the SD card Out and put in ANOTHER computer. Your mac for example. Then edit the file. Then put it back and start again.
I don’t know Mac or cyberduck. If you are root on the mac you should be able to edit the file. If it doesn’t work I’ve no ideas.
I´ve already tried this. Mounted the SD-Card to my mac, and had no permisson. I´ll try that again in half an our - first kids must go to bed 
Get a proper computer. 
I´m not able to edit the sudoers file.
Mounting it on a MAC or in WIN - I don´t have the permission…
No Ideas anymore…
I think I´ll have to configure the Raspberry completely new 
On what computer did you install openHAB?
Raspberry PI
Take the SD card out.
Put it in your mac
Edit the file
That doesnt work for me. If I mount the SD Card on my Mac I have only read-permissions…
I try.
If it works, how do I repair the sudors file?
THX a lot
Put back to what it was
If you can’t
You’ll have to format your card and start again
First of all, I have to thank you very much!!!
Downloading my sudoers file works now - the line including
root ALL=(ALL:ALL) ALL
openhab ALL=NOPASSWD: /opt/raspberry-remote/send*
is wrong. I hope deleting the line
openhab ALL=NOPASSWD: /opt/raspberry-remote/send*
solves my Problem!
Also as root I´m not able to edit or replace the sudoers file… 
I think I will start completely new…
Just to give a push in the right direction, I think you don’t need root privileges for what you want to do.
Also the posted tutorial you used, uses the openhab1 exec binding. Have a look here for setting user permissions ( allowing gpio without root privileges) and the usage of openhab 2 exec binding.