Troubles with gnujump...

Gnujump works for me on amd64. Are you on 32 or 64 bit? (system settings -> system info)

That file is installed by the gnujump-data package, perhaps try reinstalling it.

I removed all and reinstalled, but nothing. I'm on 64 bit, but with Dagda it worked.

gnujump usually didn't work for me, for example, on acer aspire one. After a jump or like that it crashed. Maybe it requires video acceleration or so. I tried it again on a most capable computer with trisquel 4.5 and it worked well, although strange effect sometimes remains on the menu, making it difficult to watch.
Maybe the game is not very stable.

When I was on Trisquel 5.0 everything worked well, very well!!
Now it doesn't open.... =(

Matsetes, have you tried to remove the brigantia package and install the 'old' dagda version ?

What do you mean?

I mean you should try removing the brigantia gnujump packages as you already said you did and install the 'old' dagda packages and see if they work for you; because you said 'When I was on Trisquel 5.0 everything worked well'.

How can I install the Dagda package?

GDebi gave me an error: dependence can not be satisfied gnujump-data = (some numbers that I forgot)

Matsetes, you can either download the package and his dependencies from here and install with dpkg (ex: dpkg -i *.deb) after you first removed the brigantia version.

Or, you can edit the sources.list file (sudo gedit /etc/apt/sources.list) and comment the brigantia sources (by putting # in front of the line), then add the dagda source (deb http://archive.trisquel.info/trisquel/ dagda main) at the bottom, then save and close. I'll just put the commands from here:

sudo apt-get autoremove gnujump
sudo apt-get update
sudo apt-get install gnujump

Afterwards, you must reverse the changes in the sources.list file and run 'sudo apt-get update' again.

If the game still doesn’t work you can try checking the directory and the file permissions from the error (/usr/share/games/gnujump/skins/default/config.theme), and eventually remove the '/usr/share/games/gnujump' folder altogether and reinstall the game; perhaps you should start with this.

I fixed it installing the previous version.
Where I have to say that there are that tipe of troubles? It's very important to fix them!