SQL Status:42883

Hi Postgres professionals,

I hope someone is able to give some advice to the following matter:

I created two plpgsql functions, which appear in pgAdminIII as
expected. The first one works fine, it has only four arguments. The
other one has 10 arguments and I have got the error

FEHLER: Funktion md.insertuser(unknown, unknown, unknown, integer, unknown, unknown, unknown, unknown, integer,
timestampwith time zone) existiert nicht 
SQL Status:42883
Hinweis:Keine Funktion stimmt mit dem angegebenen Namen und den Argumenttypen überein. Sie müssen möglicherweise
ausdrücklicheTypumwandlungen hinzufügen. 
Zeichen:15

Ok the message seems to be clear, I have to add some casts (why by the
way, the other function didn't need any cast?)

If I try it again, I'll get:

FEHLER: Funktion md.insertuser(character varying, character varying, timestamp without time zone, integer, character
varying,character varying, character varying, timestamp without time zone, integer, timestamp with time zone) existiert
nicht
SQL Status:42883
Hinweis:Keine Funktion stimmt mit dem angegebenen Namen und den Argumenttypen überein. Sie müssen möglicherweise
ausdrücklicheTypumwandlungen hinzufügen. 
Zeichen:15

I have no idea what to do, because the casts happened, the function
has already been there, it should work, but it don't work? The
argument list matches exactly.  I tried a
lot of things, e.g. creating the function without any function, to be
sure there is no fault within the function body.

I'm grateful for every tip!

Andreas