From: Torsten Hennig on
> u can ignore above message..
>
> the following link shows the exact errors i have in
> my code, so I got the explanation now...:
> http://www.mathworks.fr/support/solutions/en/data/1-AH
> E4PX/index.html?product=SL&solution=1-AHE4PX

You have a second-derivative term in your PDE ;
so pdepe can be used to solve your equation.

The reason for the error messages is most probably
a mistake in the user-defined subroutines you supply.

Best wishes
Torsten.