contretemps 
あいにくな出来事、意外な故障
1.an inopportune occurrence; an embarrassing mischance: He caused a minor contretemps by knocking over his drink.
Citations for vernissage
Pan had been amongst them--not the great god Pan, who has been buried these two thousand years, but the little god Pan, who presides over social contretemps and unsuccessful picnics.