Question: Ridiculous error message in DEplot; what does it mean, really?

I have a rather simple 2nd order ODE that I'm trying to plot. First, the ODE:

deqn1 := diff(x(t), (t$2)) = -2*(diff(x(t), t))-25*x(t)

Then the DEplot:

DEplot(deqn1, t = 0 .. 10, [[x(0) = 1, (D(x))(0) = 0]], stepsize = .1, linecolor = blue, thickness = 1)

And the error message:

Error, (in dsolve/numeric/process_input) invalid specification of initial conditions, got (D(x))(0) = 0

Now, anytime an equation value is a constant (x(0) = 1), the derivitave at that point is 0, so the error message is ridiculous on the face of it.  Can anybody hazard a guess as to what's really going on, here? And, of course, how I can fix it....

Thanks in advance

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