CMake Error in rosmsg tutorial

edit

I am in the tutorial at CreateMsgAndSrv and got stuck at chapter 3. Running the command

$ rosmsg show beginner_tutorials/Num

got me the following

Unable to load msg [beginner_tutorials/Num]: Cannot locate message [unint8] in package [beginner_tutorials] with paths [['/home/aha/catkin_ws/src/beginner_tutorials/msg', '/home/aha/catkin_ws/devel/share/beginner_tutorials/msg']]

and searching the web for a solution I stumbled upon a thread where someone had somewhat the same problem and said that he made a

catkin_make install

after the changes at the package.xml and CMakeLists.txt which I did not. But it made sense so I ran the command and then got the following error during the install process

CMake Error at /home/aha/catkin_ws/build/beginner_tutorials/cmake/beginner_tutorials-genmsg.cmake:3    (message):                                                                                             Could not find messages which                                                                          '/home/aha/catkin_ws/src/beginner_tutorials/msg/Num.msg' depends on.                                    Did you forget to specify generate_messages(DEPENDENCIES ...)?                                                         Cannot locate message [unint8] in  package [beginner_tutorials] with paths [['/home/aha/catkin_ws/src/beginner_tutorials/msg']]                                                                                    Call Stack (most recent call first): /opt/ros/kinetic/share/genmsg/cmake/genmsg-extras.cmake:307 (include) beginner_tutorials/CMakeLists.txt:71 (generate_messages)

But I followed the tutorial as it is written and did not forget to specify/uncomment "generate_messages". As I am a Newbie, I am kind of lost now and do not really know how to proceed. Can someone help me out?

System is Ubuntu 16.04 LTS, the ROS-Version is Kinetic and I added

source /opt/ros/kinetic/setup.bash

and

source ~/catkin_ws/devel/setup.bash

to my ~/.bashrc. Hope this sufficient information for the beginning...

EDIT1: Content of package.xml:

<?xml version="1.0"?>
<package format="2">
  <name>beginner_tutorials</name>
  <version>0.0.0</version>
  <description>The first test package</description>

  <maintainer email="xxx">xxx</maintainer>

  <license>GPLv3</license>

  <buildtool_depend>catkin</buildtool_depend>
  <build_depend>roscpp</build_depend>
  <build_depend>rospy</build_depend>
  <build_depend>std_msgs</build_depend>
  <build_depend>message_generation</build_depend>
  <build_export_depend>roscpp</build_export_depend>
  <build_export_depend>rospy</build_export_depend>
  <build_export_depend>std_msgs</build_export_depend>
  <exec_depend>roscpp</exec_depend>
  <exec_depend>rospy</exec_depend>
  <exec_depend>std_msgs</exec_depend>
  <exec_depend>message_runtime</exec_depend>


  <export>

  </export>
</package>

Content of CMakeLists.txt:

cmake_minimum_required(VERSION 2.8.3)
project(beginner_tutorials)

find_package(catkin REQUIRED COMPONENTS
  roscpp
  rospy
  std_msgs
  message_generation
)

add_message_files(
 FILES
 Num.msg
)

generate_messages(
 DEPENDENCIES
 std_msgs
)

catkin_package()

include_directories(
  ${catkin_INCLUDE_DIRS}
)

Content of Num.msg:

int64 sum
string first_name
string last_name
unint8 age
uint32 score