as the error says, "required 2.64174 BTS " - not BTC, BT"S".
for may case, while I thought OL takes transmission free in BTS, I prepared approx. 5BTS separately when I send 1BTC. Then, it worked. Fee was charged in BTS(not BTC) seat as default.
Yes, as I have seen sending like 5 BTS to an account unfreezes the "fee" option, but I have also seen where you don't need to send BTS to the account to get it active. I have forwarded this information to the Blocktrade team, and will know within 24 hours if it is a problem with their protocol or not.
Cheers!
Chris