It did launch, though the rocket broke into pieces shortly after launch. Maybe the west was trying to help the new leader avoid embarrassment when they begged him not to fire the rocket, which violated UN resolutions. The Guardian:
A much-heralded test of North Korea's rocket technology has ended in failure and embarrassment for the regime in Pyongyang less than two minutes after lift-off.
The Unha-3 rocket, which Washington claimed was cover for a ballistic missile test and drew condemnation from around the world, exploded into about 20 pieces fell into the Yellow Sea.
The North Koreans ignored eleventh-hour pleas from the US, South Korea and Japan not to go through with the launch, insisting its sole purpose was to put an earth observation satellite into orbit.