You should not need to run Code_Saturne using sudo (if you do, it means you have an installation problem).
Did you move your case after calling "code_saturne create" ? It seems the path for your case is ~2D/2D, while the script is searching for 2D.
In general, with Code_Saturne versions < 2.1, you should initially build both a study (-s option to code_saturne create) and a case (-c option). You may then later add cases in the study. Alternatively, you may simply build a case, then create a "MESH" directory at the same level as the case (this is the directory structure the runcase script will be looking for).
In any case, if you move a case, you must update paths inside the runcase script.
If your problem does not come from this, can you post a copy of your runcase and case.xml files ?
I run the Gui using sudo because this make that the graphical interface looks fine, otherwise when i try to press the icons a little black box is showed. (take a look of the screenshots)
I didn't move the case.
I all ready have build the study, case and mesh directory, but I'm having the same error.
What should I do to "reInstall" the latest version of C-S in a recently cleaned version of Ubuntu 11.04? The first time that I try to install the program, I download all the files and then try to compile but without success. Lately I have used the python script to install C-S, do I have to do something else after running the script?
I have the explanation for the black boxes (I had them on Ubuntu also): they are simply due to the choice of color/background color in the Ubuntu default gtk themes (the Code_Saturne GUI uses qt4, and always uses black text, so we might have to find an improvement there).
In any case, using a slightly lighter background for help bubbles will solve that problem (sudo/root probably uses a slightly different theme).
I suggest then running without sudo, and checking if you still have the same problem.
Otherwise, installing with the script should be fine, and there is nothing else to do.