OK I had a look and I will post a short and a long explanation:
You can delete the file
wallets-faucet/includes/third-party/class-tgm-plugin-activation.php and your immediate problem should go away.
TGMPA is a very common library for tracking dependencies among wordpress themes and plugins. For this reason, many authors use it. The version that I have included into the faucet plugin, TGMPA 2.6.1, is careful enough to not re-declare itself if it is already declared. The error you are getting is triggered from your meta4delicious theme, which I assume has an older version of TGMPA, that did not do that check.
I would recommend that you let the author of that theme know about this, so they can update to a more recent TGMPA version.
Let me know if deleting the file fixes your problem.