@keniv Good work!
Yes there is a flaw in setting the default background. The error you see is minor, and will be straightened out at some point.
To set the background right click anywhere on the empty space of the desktop and drag something over from /usr/share/backgrounds into the GUI form.
No mime types are yet declared so to set run action right click on the file, for example test_example.jpg and then in the GUI form type "viewnior" or drag and drop the binary into the GUI. From then on when you click on a .jpg in the file manager it will open up in viewnior
You can do this to every extension type. Another example right click on a .sfs and type "filemnt" into the command box in the GUI form. now clicking on an SFS will mount it and you can look inside in the file manager. Click on it again and it will umount the sfs. Also use "filemnt" as the Run Action for clicking on an ISO file and it will sdo the same thing as if it were a SFS.
I will also keep on track to get a firewall configuration going.