Question: unable to handle elliptic PDEs

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

sys := {l1, l2}

IBC := {ui(-500, t) = 0, ui(500, t) = 0, ur(-500, t) = 0, ur(500, t) = 0, (D[1](ui))(-500, t) = 0, (D[1](ui))(500, t) = 0, (D[1](ur))(-500, t) = 0, (D[1](ur))(500, t) = 0}

sol := pdsolve(sys, IBC, [ur(e, t), ui(e, t)], numeric)

Help please!

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