well, "počas večera" is OK, "vo večere" is not so clear and more common is just to say "večer". If you ment "in the evenig" like I wil do it ... Urobím to večer (or) počas večera. And "vo večere" I literally see "in the dinner" :-)

počas večera is good. but vo večere is not correct .. corecct is na večere- in Restaurant .. :)