I don't get why I keep getting the Solve::ivar: 0 is not a valid variable. >> message. Here is the code:

Solve[{Rh + T1/Sqrt[2] + T2 == 0, Rv + T1/Sqrt[2] == 0, -(T1/Sqrt[2]) + T5/Sqrt[2] + T6 == 0, -(T1/Sqrt[2]) - T3 - T5/Sqrt[2] == 0, -T2 + T4 == 0, T3 == 0, 18 - T6 + T9/Sqrt[2] == 0, -T7 - T9/Sqrt[2] == 0, -T4 - T5/Sqrt[2] + T8 == 0, -45 + T5/Sqrt[2] + T7 == 0, -T8 - T9/Sqrt[2] == 0, N + T9/Sqrt[2] == 0}, {Rh, Rv, T1, T2, T3, T4, T5, T6, T7, T8, T9, N}] Solve::ivar: 0 is not a valid variable. >> Solve[{Rh + T1/Sqrt[2] == 0, Rv + T1/Sqrt[2] == 0, -(T1/Sqrt[2]) + T5/Sqrt[2] + T6 == 0, -(T1/Sqrt[2]) - T5/Sqrt[2] == 0, T4 == 0, True, 18 - T6 + T9/Sqrt[2] == 0, -T7 - T9/Sqrt[2] == 0, -T4 - T5/Sqrt[2] + T8 == 0, -45 + T5/Sqrt[2] + T7 == 0, -T8 - T9/Sqrt[2] == 0, N + T9/Sqrt[2] == 0}, {Rh, Rv, T1, 0, 0, T4, T5, T6, T7, T8, T9, N}]

I alredy did two similar problems and I didn't had this problem. Somebody knows how to solve it?