cannot plot in scilab

Hi
I am trying to plot in scilab and instead I am getting the following error.

–>y = .1 .2 .75 1.5 2.1 2.4 ]’
y =

0.1   
0.2   
0.75  
1.5   
2.1   
2.4   

–>x = .5 .7 .9 1.3 1.7 1.8 ]’
x =

0.5  
0.7  
0.9  
1.3  
1.7  
1.8  

–>plot2d(x,y,style=-1);
Warning !!!
Scilab has found a critical error (Unknow exception).
Save your data and restart Scilab.

Warning: stack problem…, cleared.

of course no plot comes up.
Any dieas how to tackle this thing?

Thnaks