You may not have enough available disk space but Armory didn't that far enough yet.
Assuming /home/0rphane/.bitcoin/ is the path to your Core folder, start Armory with this command line argument: --satoshi-datadir=/home/0rphane/.bitcoin/
It works now, here's how i did:
a) starting bitcoin-qt itself in its /bin DIR, being able to follow initialization assistant pointing then to the chain (bitcoin-qt itself was not aware of it's very own data?!)
b) issuing the suggested command pointing to the correct data DIR, in my case on an external HDD
Think i have kind of weird setup, i'd better move installation to a dedicated machine.
update: Thank you ! That did the trick, i also added --dbdir=/external space, to get around issues with the small ssd.