Problem with legend in plot

Hi
I am using r07a matlab and am facing problem with legend
the error says:
??? Error using ==> hgconvertunits
Invalid object handle.

Error in ==> legend>make_legend at 386
lh=scribe.legend
(ha,orient,location,position,children,listen,strings,proparg
s{:});

Error in ==> legend at 285
[h,msg] = make_legend(ha,varargin(arg:end));

Error in ==> Untitled at 2
plot(rand(10,1),'-o');legend('x');

--
i am using a simple plot:
figure;
plot(rand(10,1),'-o');legend('x');


Please suggest wht is the problem

.