[sitl-2] process has died after roslaunch px4 mavros_posix_sitl.launch

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Hello, I was able to communicate with Gazebo some days ago in an old PC. I changed the computer but now I am unable to do so. With all the requirements installed, when I follow these steps:

cd <Firmware_clone>
make posix_sitl_default gazebo
source ~/catkin_ws/devel/setup.bash    // (optional)
source Tools/setup_gazebo.bash $(pwd) $(pwd)/build/posix_sitl_default
export ROS_PACKAGE_PATH=$ROS_PACKAGE_PATH:$(pwd)
export ROS_PACKAGE_PATH=$ROS_PACKAGE_PATH:$(pwd)/Tools/sitl_gazebo
roslaunch px4 mavros_posix_sitl.launch

Gazebo opens but with these errors in console:

process[sitl-2]: started with pid [16009]
node name: sitl
data path: /home/nando/src/Firmware
commands file: /home/nando/src/Firmware/posix-configs/SITL/init/lpe/iris
ERROR [Unknown] Error creating symlink /home/nando/src/Firmware/ROMFS -> /home/nando/.ros/ROMFS
Restoring terminal

[sitl-2] process has died [pid 16009, exit code 255, cmd /home/nando/src/Firmware/build/posix_sitl_default/px4 /home/nando/src/Firmware /home/nando/src/Firmware/posix-configs/SITL/init/lpe/iris __name:=sitl __log:=/home/nando/.ros/log/52da88aa-e562-11e7-9b53-b05adae3a335/sitl-2.log].
log file: /home/nando/.ros/log/52da88aa-e562-11e7-9b53-b05adae3a335/sitl-2*.log

When running the first command

make posix_sitl_default gazebo

I have to close gazebo with ctrl + c, I don't remember if I did that in my last installation but it gives this error that may be the cause of my problems. However if I don't do that it will run forever:

Exiting...
Shutting down
Restoring terminal
ninja: build stopped: interrupted by user.
Makefile:147: recipe for target 'posix_sitl_default' failed
make: *** [posix_sitl_default] Interrupt

Can you guess where the problem can be? Any help would be appreciated.