Trying to book LHR-VIE and VIE-BER online and after various attempts, the web site just would not let me.

At first, I got an error message after entering my details that my name and FF# do not match. (My FF is United and I had removed my middle initial on my account since signing up on LH.com).

I tried three times, but error about names not matching keep popping up. So I closed Safari and tried without logging in. It kept popping up an 'unknown error' message. So I closed Safari then used Chrome without logging in, and same 'unknown error."

I called the call center (Philippines?) but there is a USD100 surcharge for booking by phone!?!?

Finally, I tried mock-booking a roundtrip LHR-VIE-LHR and it did go to the next page. So one-way international itineraries are not allowed online?

Edit:
After trying again, this time separate, LHR-VIE, and VIE-BER tickets, it was now allowing me to book them separately. However, the cost of the two combined is another USD100 above what the phone agent quoted!