Same here.. I can easily import a board exported as JSON from Trello, but not a board exported from Wekan (running on another machine). Using 0.10.1 (both source and destination boards), installed with autoinstall_wekan.sh, Linux Mint 17.3.
Seems to fail when dealing with the users? Even though I had exactly same users in both installs..
Alternatively, I believe one could manually copy the databases.. Any hints on that?