Which Eclipse version are you using?
I suggest you to install this one:
Version Luna SR1 (4.4.1) from IoT Download - Linux* Development Kit
After you extract the files, you only needs to run: ./devkit-launcher
I saw in your log that the error is related to the location of the files, /home/lea/Downloads/iotdk-ide-linux//home/lea/Downloads/iotdk-ide-linux. Try to move the iotdk-ide-linux folder to /home/lea/ the launcher should look for in the location /home/lea/Downloads/iotdk-ide-linux but it is using the other location, that could be the root of the issue you are having. Try with this and let us know the outcome.