FindFit::eit Error Message in Mathematica

*To*: mathgroup at smc.vnet.net*Subject*: [mg128616] FindFit::eit Error Message in Mathematica*From*: benz43 <sittichaisahachaiwatana at hotmail.com>*Date*: Sat, 10 Nov 2012 02:06:52 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*Delivered-to*: l-mathgroup@wolfram.com*Delivered-to*: mathgroup-newout@smc.vnet.net*Delivered-to*: mathgroup-newsend@smc.vnet.net

Hi! I'm trying to fit the curve with my data and I got an error message that I don't have a clue what to do next, plz help! (I'm very new to Mathematica) this is the equation which is quite complex http://www.4shared.com/photo/ybdQBp4m/Equation.html? Equation = ((1 - ((Log[(1 + (x1/RMS1))])/(Log[(1 + ((10^6)/ RMS1))])))*(1/(Log[(Exp[1] + ((x1/a1)^n1))]))^m1) this is my data data = {{3, 0.99}, {4, 0.99}, {4, 0.53}, {6, 0.12}, {15, 0.12}, {21, 0.12}, {21, 0.12}, {34, 0.12}, {33, 0.12}, {96, 0.11}} FindFit[data, {((1 - ((Log[(1 + (x1/RMS1))])/(Log[(1 + ((10^6)/ RMS1))])))*(1/(Log[(Exp[1] + ((x1/a1)^n1))]))^m1), RMS1 > 0, a1 > 0, n1 > 0, m1 > 0}, {RMS1, a1, n1, m1}, {x1}] it gives me error message FindFit::eit: The algorithm does not converge to the tolerance of 4.806217383937354`*^-6 in 500 iterations. The best estimated solution, with feasibility residual, KKT residual or complementary residual of {2.34477*10^-6,0.0000672552,7.34805*10^-7}, is returned. >> {RMS1, a1, n1, m1} = {5001580, 3.99808, 6550.2, 0.233221} How can i fix this error ? Thanks for any help !