Help fixing some functions in R for copula distributions

hello. i have some R code that estimates an index popular in the quantitative social sciences called the polychoric correlation coefficient. the difference is that instead of assuming a multivariate normal distribution an elliptical copula distribution is assumed as a model.

the R script works fine, i generate good enough estimates but i cannot, for the life of me, get appropriate standard errors (SE). there are functions in R that estimate this index via maximum likelihood so i have been using these as comparison to evaluate my results. they should be the same (within reasonable rounding error of course) but mines are far, far off.

i think this has more to do with the fact that i'm an intermediate-level learner of R/statistics and may not be fully grasping how to obtain the hessian matrix properly or how to set the likelhood function well.

your job would be to look at my R script (which otherwise works perfectly) and help me fix it to obtain standard errors that match the ones from the
already-developed functions in the 'polycor' R package.

ps- as a little bit of a guideline, this is a little more complicated than just grabing the 'optim' function, setting hessian=T and taking the square root of the inverse of the diagonal. i'm wondering if something is wrong with the likelihood function (although i hope not because the estimates i get match the ones i would expect)