I have removed (not just deactivated) both the other braintree payment plugin and a Barclays payment plugin. But I am still getting a 500 server error on wp-admin when I activate the plugin after installation. There’s nothing in the php or apache error logs to give me a clue.
WordPress 4.3.3 running WD FashionZozza theme. Woocommerce 2.4.10.
https://wordpress.org/plugins/woo-payment-gateway/