I thought you were trying to use this:
[How-to] Add more tabs to the vB 3.7 profile pages What you posted is not what the article says to do. You need to make a plugin using the member_build_blocks_start hook and that is what you need to post. You said you tried it but it didn't work. So, I'm wondering what you put in the plugin that didn't work. You really need to read that article and follow the instructions.