it really does come down to what i've written here:
so this is going to be a problem, because the items in the list are not named:so there's two important things to check here. the first is that the table contains suitable columns, secondly that the items in the values list have names which match those columns.
values <- as.list(combined_UA_df[2, colNo])
if you go names(values) i think you'll get NULL
instead you could do:
values <- list(xxx=combined_UA_df[2, colNo])
where xxx is the name of the column you want the value to appear in.
if you're not familiar with named lists in R, i can appreciate this can be a bit frustrating to figure out.
jonathon