[Koha] Internal server error when trying to open Budget or Funds

Hi When trying to click "Budgets" or "Funds" in Koha menu "Administration > Acquisition parameters" just a blank page appears, saying "Internal server error". Like this, of course, no new budget or fund can be added. I am experiencing this on Koha 16.11.1 as well as on Koha 17.05.1 (but not on Koha 16.11.4). I tried this as a user with the rights of a "superlibrarian" as well as with a user with fewer permissions. Has anyone experienced the same and can help, or should I maybe open a bug case? Best wishes: Michael -- Geschäftsführer · Diplombibliothekar BBS, Informatiker eidg. Fachausweis Admin Kuhn GmbH · Pappelstrasse 20 · 4123 Allschwil · Schweiz T 0041 (0)61 261 55 61 · E mik@adminkuhn.ch · W www.adminkuhn.ch