ValueError: Computation failed since Maxima requested additional constraints

edit

I am trying integrate an exponential decay function.

reset()
var('t,v')
tmax=0.01

fx=((1.66533453693773e-16 +
1.99493199737333e-17*i)*e^((2.57571741713036e-13 -
1.81898940354586e-12*i)*t) + (1.00000000000000 -
1.99493199737333e-17*i)*e^(-(30.0000000000003 - 12784.0000000000*i)*t))
forget()
assume(v>0)
integrate(fx*exp(-i*v*t),(t,0,tmax))

the error shows

Computation failed since Maxima requested additional constraints; using the 'assume' command before evaluation *may* help (example of legal syntax is 'assume(-%i*v/(0.257571741713036e-12-0.181898940354586e-11*%i)
>0)', see `assume?` for more details)
Is -%i*v/(0.257571741713036e-12-0.181898940354586e-11*%i)
    +12784.0*%i/(0.257571741713036e-12-0.181898940354586e-11*%i)
    -30.00000000000026/(0.257571741713036e-12-0.181898940354586e-11*%i)-1
    equal to -1?

no assumption working. please help.