ok, i used the power word "websearch" and found a french forum where there was a patch for our little - european wide - problem.
unzip the file in ..\Temple of Elemental Evil\data\scr
it fixes the dialogue and you get the holy sword.
strange thing: my party is around 7th lvl and even if the sword is labelled +1, it is effectively +3 (compare hit bonus and check via craft wp n armor). its good news anyway...
hope the bug fixes whatever the language.