I just checked the package edit page and I am getting similar errors there:
Link Template: Warning: file_get_contents(C:\wamp\www\PJI\wp-content\plugins\download-manager//templates/email-templates): failed to open stream: Permission denied in C:\wamp\www\PJI\wp-content\plugins\download-manager\add-new-file.php on line 632
Page Template: Warning: file_get_contents(C:\wamp\www\PJI\wp-content\plugins\download-manager//templates/email-templates): failed to open stream: Permission denied in C:\wamp\www\PJI\wp-content\plugins\download-manager\add-new-file.php on line 661