Apple Inc. said Monday it has sold 1 million iPhones in the three days following the release of the latest model on Friday. “IPhone 3G had a stunning opening weekend,” said Steve Jobs, Apple's chief executive, in a statement Monday. But the launch was plagued by software problems. All the new iPhones had to connect to Apple's servers for activation, which quickly overloaded them. Lines of customers built in stores as employees were unable to get the phones working. Additionally, new software was released for the old iPhone, which required reactivation of those phones. Many owners of the older phone were left with unusable units. The iPhone 3G was launched simultaneously in 21 countries, including the US. Apple had sold about 6 million units of the first-model iPhone since it launched in the US a year ago. The company has set a goal of selling 10 million iPhones by the end of 2008.