Danke erstmal - das war's aber nicht. Hier mal die komplette Fehlemeldung:
UPDATE vendor SET vendornumber = ?, name = ?, greeting = ?, department_1 = ?, department_2 = ?, street = ?, zipcode = ?, city = ?, country = ?, homepage = ?, contact = ?, phone = ?, fax = ?, email = ?, cc = ?, bcc = ?, notes = ?, terms = ?, discount = ?, creditlimit = ?, business_id = ?, taxnumber = ?, language = ?, account_number = ?, bank_code = ?, bank = ?, iban = ?, bic = ?, obsolete = ?, direct_debit = ?, ustid = ?, payment_id = ?, taxzone_id = ?, language_id = ?, username = ?, user_password = ?, v_customer_id = ?, curr = ? WHERE id = ? (L28097, Meier GmbH, Firma, Verkauf, , Am Stadtrand 77, 03042, Rauschenbach, Irgendwo, , , , , , , , Testlieferant, , 0, 0, , , , , , , , , f, f, , 1121, 0, , , , , EUR, 9245)
FEHLER: record "old" has no field "datevexport"
CONTEXT: PL/pgSQL function "set_datevexport" line 1 at IF