* Shares fall by more than 4 pct (Recasts, adds details, updates shares): BERLIN (Reuters) - German lighting group Osram said on Thursday that talks with Bain Capital and Carlyle Group were continuing, after Manager Magazin said the private equity firms could walk away from a possible takeover. The Munich-based group, which is grappling with weakness in the automotive industry and a broader economic slowdown, said in February that Bain and Carlyle were looking at whether to jointly bid for up to 100 percent of its shares. “We are currently in good talks with Bain Capital and Carlyle.