May 15 (SeeNews) - Croatian wireless operator Vipnet, a unit of Austria's Mobilkom, had 42.4 million euro ($65.8 million) in operating income before depreciation, amortisation and impairment charges (adjusted EBITDA) in the first quarter of the year, up from 37.9 million euro a year earlier, Mobilkom's parent, Telekom Austria said on Thursday.