Trouble adding JavaScript inside a custom module
It looks like it's due to the second implementation of drupal_get_path().

You're passing through mymodule2 as the argument, where it should just be mymodule.

e.g.

function mymodule_init() {
  drupal_add_js(drupal_get_path('module', 'mymodule') .'/js/mymodule.js');
  drupal_add_js(drupal_get_path('module', 'mymodule') .'/js/mymodule2.js');
}


On another note, if the JavaScript needs to be added on every page (as I'm guessing it does with the implementation of hook_init) then you might be better off adding your scripts in using scripts[] in the module's .info file


  scripts (Optional) 
  
  You can now add Javascript in the module's .info
  file if it should be added on every page. This allows Javascript to be
  aggregated in an optimal way, and is the preferred method of adding
  Javascript that most visitors will need on a typical site visit


Source:  Writing module .info files

References:

drupal_get_path(); API Docs

Managing JavaScript in Drupal 7

Writing module .info files