In searching, error 1050 shows up with other 3rd party software scripting nodes for a variety of reasons which may be hard to immediately track down. Note the following:
Error 1050 on Second Execution of My MATLAB® Script Node
To troubleshoot, have you tried running the built-in Scilab examples? Those are found under <LabVIEW Installation Root>\examples\Scilab.
Have you ensured the Scilab is otherwise running fine on your machine?
Examples work !
And since I run examples my VI works too...
Strange but it works !