Error using eigs: Error with ARPACK routine dnaupd

Hi, I'm trying to use a script using eigs function:

 opts.disp=0; 
  [v d]=eigs(A,B,k,'lm',opts);

[Note: the original function used `la`, but my matrix doesn't seem symetrical]

Here's the error message I received: ??? Error using ==> eigs at 255 Error with ARPACK routine dnaupd: info = -9999 [Note: it's the same error message whereas i`m using `lm`, `lr`or `li`(I'm a real newbie..)]

Thanks

Marie-Andrée