[R] Problems to obtain standardized betas in multiply-imputed data

[CHATTON Anne]

Dear all,

I am having problems in obtaining standardized betas on a multiply-imputed data set. Here are the codes I used :
imp = mice(data, 5, maxit=10, seed=42, print=FALSE)
FitImp <- with(imp,lm(y ~ x1 + x2 + x3))
Up to here everything is fine. But when I ask for the standardized coefficients of the multiply-imputed regressions using this command :
sdBeta <- lm.beta(FitImp)
I get the following error message: 
Error in b * sx : argument non numérique pour un opérateur binaire

Can anyone help me with this please?

Anne