i keep getting this two errors for my codes.

var1 = graph1[input1];
soln3 = Simplify[ Solve[{il3 == (k((vdd - vin - vt)(vdd - vo[t]) - ((vdd - vo[t])^2/2)) - (k/2(vin)^2)), vin == mt}, il3, {vin}]];

1) Solve was unable to solve the system with inexact coefficients. The answer was obtained by solving a corresponding exact system and numericizing the result. >>

stage2[t] = il3 /. Part[Part[soln3, 1], 1];
soln4 = NDSolve[{vo'[t] == stage2[t]/c0, vo[input1] == var1}, {t, input1, vdd/m}];

2) NDSolve::argm: NDSolve called with 2 arguments; 3 or more arguments are expected. >>

keep getting both warning/ error.......