I made some progress.
First of all, the crash was probably some compatibility problem between the pre-built cgminer version and xubuntu 12.04. I installed xubuntu 13.04 and managed to run cgminer.
Second, the remote running via ssh problem was solved (I think) using this guide:
http://devgurus.amd.com/thread/159566Now I have a problem with the second card. This is the output from cgminer:
cgminer version 3.7.2 - Started: [2014-01-02 15:49:38]
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(5s):704.6K (avg):750.0Kh/s | A:896 R:0 HW:2 WU:659.8/m
ST: 2 SS: 0 NB: 1 LW: 12 GF: 0 RF: 0
Connected to gigahash.wemineltc.com diff 128 with stratum as user myuser.1
Block: a87d75d0... Diff:3.17K Started: [15:49:39] Best share: 1.17K
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[P]ool management [G]PU management [S]ettings [D]isplay options [Q]uit
GPU 0: 61.0C 5205RPM | 745.5K/736.6Kh/s | A:896 R:0 HW:0 WU: 659.8/m I:20
GPU 1: 41.0C 5166RPM | 29.82K/13.39Kh/s | A: 0 R:0 HW:2 WU: 0.0/m I:20
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[2014-01-02 15:49:39] Network diff set to 3.17K
[2014-01-02 15:49:40] GPU1: invalid nonce count - HW error
[2014-01-02 15:49:44] API running in IP access mode on port 4028 (17)
[2014-01-02 15:49:49] Pool 0 difficulty changed to 128
[2014-01-02 15:49:49] Stratum from pool 0 requested work restart
[2014-01-02 15:49:49] Accepted 48dd41c2 Diff 899/256 GPU 0 pool 0
[2014-01-02 15:49:54] Accepted 01ecd9ad Diff 133/128 GPU 0 pool 0
[2014-01-02 15:50:07] Accepted 0180d290 Diff 170/128 GPU 0 pool 0
[2014-01-02 15:50:14] Accepted 01b9faf3 Diff 148/128 GPU 0 pool 0
[2014-01-02 15:50:48] Accepted 37d37e25 Diff 1.17K/128 GPU 0 pool 0
[2014-01-02 15:50:52] Accepted 012ef071 Diff 216/128 GPU 0 pool 0
