I want to install Braintree payment method on magento 1.9.3. When I enable extension I get HTTP error 500. Braintree extension was copy-paste from our old store v1.7 and worked fine.
I was trying with compiler enable/disable, uploading missing files to /include/src/ and still not working.
2017-03-15T10:11:51+00:00 ERR (3): Warning: include(/**********/public_html/includes/src/Braintree.php): failed to open stream: No such file or directory in /**********/public_html/includes/src/Varien_Autoload.php on line 94 2017-03-15T10:11:51+00:00 ERR (3): Warning: include(): Failed opening '/**********/public_html/includes/src/Braintree.php' for inclusion (include_path='/**********/public_html/includes/src:.:/usr/local/php55/lib/php') in /**********/public_html/includes/src/Varien_Autoload.php on line 94
You don't have to do anything about includes/src directory. It's auto-generated by Magento, so it doesn't matter what are you doing in it.
To install Braintree module, you have to copy appropriate files from app/code directory, and module XML file from app/etc/modules/. Probably you have some files in app/design/frontend and app/design/adminhtml which should be copied. It's the best if you have extension in ZIP, so it's easy to install it. Otherwise, you need some experience to find all those files in your old store code.
If you're sure that you've copied all files from those locations, then just disable compilation, and clear the cache. Then check if everything is working properly.
If it's not working, then you're probably missing some files from old 1.7 store (missed to copy them into new Magento). Otherwise, if it works, you can try to turn on the compilation.
One note about compilation: It's unnecessary to use it today because PHP possesses good opcode caches, so it doesn't give too much benefit.