I try just following the tutorial, but adding a vector for the parameters as well, unfortunately that doesn't work:
using Optimization, OptimizationBBO, Random
Random.seed!(100)
rosenbrock(x, p) = (p[1] - x[1])^2 + p[2] * (x[2] - x[1]^2)^2
x0 = zeros(2)
optf = OptimizationFunction(rosenbrock, Optimization.AutoForwardDiff())
prob = OptimizationProblem(optf, x0, [1.0, 100.0])
ensembleprob = Optimization.EnsembleProblem(prob, [x0, x0 .+ rand(2)]) # Works
ensembleprob = Optimization.EnsembleProblem(prob, [x0, x0 .+ rand(2)], [[1.0, 100.0], [1.0, 101.0]]) # Errors