I'm trying to make a CFA using R. Prior to this, I've imputed all missing data using regression estimation, so there are no negative values. Still, I nonstop get the following warnings in R:

Warning in eval(expr, envir, enclos) :

Could not compute QR decomposition of Hessian.

Optimization probably did not converge.

Warning in sqrt((outer(c, c) + C^2)/N) : NaNs produced

When I've conducted this analysis using Amos, it gave me resonable goodness of fit, while in R I get huge and negative numbers. Still, I really need to do this in R.

Could you please give me an advice on what I am doing wrong and what I am missing? I have lost two days searching for answers in R manuals and on cran site, but I am new with R so therefore completly lost.

Is there a function to identify which cases produce NaN? What should I do?