st: error 506 (matrix not positive definite) when bootstrapping eigenvalue after one-way manova

["Carlo Lazzaro" <carlo.lazzaro@tin.it>]

Dear Statalisters,
before bootstrapping eigenvalue after one-way manova using auto.dta and
Stata 9.2/SE, I imposed the equality of the means in price and mpg for both
foreign and domestic cars.
When I invoked bootstrap, error message r(506) related to model term foreign
appeared.
Can anybody please give me some hint about the reason of this drawback and
how to work it around?
Thanks a lot for your kindness and for your time.
Kindest Regards,
Carlo
------------code begins-----------------------
use "C:\Programmi\Stata9\ado\base\a\auto.dta"
manova price mpg=foreign
svmat double c, name(eigen_m)
scalar sctr=trace(c)
by foreign, sort: sum price
sum price if foreign==0, meanonly
replace price=price-r(mean)+6384.682 if foreign==0
sum price if foreign==1, meanonly
replace price=price-r(mean)+6384.682 if foreign==1
by foreign, sort: sum  mpg
sum  mpg if foreign==0, meanonly
replace  mpg= mpg-r(mean)+24.77273 if foreign==0
sum  mpg if foreign==1, meanonly
replace  mpg= mpg-r(mean)+24.77273 if foreign==1
bootstrap trace(c), reps(10000) nodots strata(foreign) bca seed(12345) :
manova price mpg=foreign
failure for model term foreign
an error occurred when bootstrap executed manova
r(506);
------------code ends-----------------------


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