confidence interval of Parametric Bootstrapping

Dear All;

I wonder how can I calculate the parametric bootstrapping of the random gamma distribution?

I fitted a gamma distribution at the beginning to my data, but then when I tried to find the bootstrapping I get a lot of error messages.

a=gamfit(data); [bootstat,bootsamp]=bootstrp(1000,@gamrnd,a);

Can any one help me please about how to use parametric bootstrapping to generate random gamma distributions?

Many Thanks in advance