Hello,
You are using a version of Bitcoin and Altcoin Wallets before 6.0.0 (which is still in RC status).
Could it be that you have installed the adapter version 2.x? Please note the version requirements at the download page. You should be using version 1.2.1 with your version of the plugin.
Apologies for the confusion. This will be resolved when I finally push 6.0.0 to wordpress.org.
with regards