Parameter 1 ("$1") has been aliased with the same name as one of the columns in your table. PL/pgSQL doesn't know about context, and is substituting "$1" for that parameter alias reasoanbly enough, resulting in something like
"insert into cr_wp_presentations($1, ...)"
instead of the column name.
You can avoid problems like this by consistently prefixing your parameter aliases with "p_" just as you've used "v_" as a prefix for your variable names.
