This is the place where Robby Takac feels the flutters: onstage, a few hours before a show, right around soundcheck, when the Goo Goo Dolls’ music tends to echo off the empty seats.It’s in moments like this, before the fans show up, where Takac’s nerves creep in. Man, Takac thinks to himself in moments of self doubt. I hope these people still care.They do. The logical side of him knows that.“We haven’t sold this many tickets here since 2006,” he said, standing onstage at the Darien Lake Performing Arts Center after the Goo Goo Dolls’ soundcheck before their tour stop here last month. The band