I just tried a whole night to get GnuCash and HBCI work in Ubuntu. It's really a mess. Ubuntu does not provide gnucash-hbci for some weird reason so you have to recompile gnucash from source.
Well, after 8 hours I got aqhbci working currectly after I found out that there was a wrong IP on my card. This was definitly not aqhbci's fault but it had been of course easier if they had better error messages.
I managed to get the HBCI-Wizard in Gnucash working but I still cannot make any transaction because of some strange things in aqbanking but I try to investigate this further. Maybe I will write a wiki-page once it's finished in the ubuntu-wiki.