# DSolve is rejecting my description of a system of PDEs

I am trying to solve a system of partial differential equations using DSlove. But i get the input equations in return. Dsolve is not doing anything

 pde4 = (2 Subscript[k, 3]*
D[Subscript[s, 1][x, t, o], x, x]) + ((2 G/r^2)*
D[Subscript[s, 1][x, t, o], o, o]) + ((Subscript[k, 1] + 2 G)/r)*
D[Subscript[s, 2][x, t, o], x, o] + (Subscript[k, 1]/r) D[
Subscript[s, 3][x, t, o], x] -
u*D[Subscript[s, 1][x, t, o], t, t] == 0

pde5 = 2 G*
D[Subscript[s, 2][x, t, o], x, x] + ((2 G + Subscript[k, 1])/r)*
D[Subscript[s, 1][x, t, o], x, o] + (2 Subscript[k, 2]/r^2)*
D[Subscript[s, 2][x, t, o], o, o] + (2 Subscript[k, 2]/r^2)*
D[Subscript[s, 3][x, t, o], o] -
u*D[Subscript[s, 2][x, t, o], t, t] == 0

pde6 = (Subscript[k, 1]/r) D[Subscript[s, 1][x, t, o],
x] + (2 Subscript[k, 2]/r^2)*
D[Subscript[s, 2][x, t, o], o] + (2 Subscript[k, 2]/r^2)*
Subscript[s, 3][x, t, o] + u*D[Subscript[s, 3][x, t, o], t, t] == 0

DSolve[{pde4, pde5, pde6}, {Subscript[s, 1], Subscript[s, 2],
Subscript[s, 3]}, {x, t, o}]


Output is this same thing again. I want a general solution with arbitrary functions. I will add boundary conditions later. Can i get output in a general form?

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Offhand, there are two things that immediately appear suspicious to me: Subscript (try simple identifiers like k1, k2, ...) and the mysterious independent variable o. –  m_goldberg Oct 19 '13 at 7:40
o is nithing but theta. just for convenience's sake. –  Jairaj Mathur Oct 20 '13 at 16:44