As you say, non-integers cannot be frequency weights.
Otherwise how these weights are to be interpreted looks like
a substantive matter. You need to move upstream
towards the author or supplier of the dataset.
Agreed. If the authors have provided weights, they've also hopefully
provided information on how to use them. It might also be that, instead of
just using the weights, you want to use Stata's svy commands (e.g.
clustering and/or stratification may have been used when gathering the
data, and if so variables that indicate that are also hopefully included.)
