The system consists of 3 equationsHow can you single out one of the solutions in obtaining module and plot for it?
a := 1; m := 1/64 
l1 := 2*(diff(ur(e, t), t))+(1+tanh((1/20)*e))*(diff(ui(e, t), `$`(e, 2)))+2*a*(ui(e, t)*ur(e, t)*ur(e, t)+(ui(e, t)*ui(e, t))*ui(e, t))+m*ui(e, t)*(diff(ur(e, t)^2, e))+m*ui(e, t)*(diff(ui(e, t)*ui(e, t), e)) = 0 
l2 := -2*(diff(ui(e, t), t))+(1+tanh((1/20)*e))*(diff(ur(e, t), `$`(e, 2)))+2*a*(ur(e, t...

unable to handle elliptic PDEs
 Does this error mean that I can/t solve my PDE system by Maple?

l1 := 2*(diff(ur(e, t), t))+(1+tanh((1/20)*e))*(diff(ui(e, t), `$`(e, 2)))+2*a*(ui(e, t)*ur(e, t)*ur(e, t)+(ui(e, t)*ui(e, t))*ui(e, t))+m*ui(e, t)*(diff(ur(e, t)^2, e))+m*ui(e, t)*(diff(ui(e, t)*ui(e, t), e)) = 0

l2 := -2*(diff(ui(e, t), t))+(1+tanh((1/20)*e))*(diff(ur(e, t), `$`(e, 2)))+2*a*(ur(e, t)^3+ur(e, t)*ui(e, t)^2)+m*ur(e, t)*(diff(ur(e, t)^2, e))+m*ur(e, t)*(diff(ui(e, t)^2, e)) = 0...

How can I set  the boundary conditions? I need to specify diff(ui(e, t), e) and diff(ur(e,t),e) depending on e.  I write the rules:

> D1(e,t):=diff(ui(e,t),e);

 
> D12(e,t):=diff(ur(e,t),e);

 in order to use D1 and D12 in boundary conditions. 

I get error
> sol := pdsolve(sys, {D1(-500, t), D1(500, t) = 0, D12(-500, t) = 0, D12(500, t) = 0, ui(-500, t) = 0, ui(0, t) = 0, ui(500, t...