I watched the entire 35 min video. He did NOT say he couldn't recall Obama's position.
He was clarifying WHAT question the guy was asking him. The guy had asked if Cain agreed/disagreed with what Obama had done in Libya - but they guy hadn't said what exactly he meant. Did he mean Obama sent a basket of cookies to support the opposition? Or did he mean that Obama has supported the assassination of a foreign head of state? The question was not clear. Cain was clarifying by asking the guy questions.
That is exactly how I saw that part of the interview too.
Fortunately, conservatives generally see through the deceit of the democrat fifth column media. Herman Cain has more substance than the media want him to have, so they make up lies to try and raise his negatives in polls. They care not a whit about the man or his conservatism because they work for a certain master who is a known father of lies.