The flight crewmembers of the jumbo jet were preparing to start the engines when flight attendants (F/A's) in the forward cabin detected a faint odor prior to closing door 1L. The source could not be determined, so the door was closed in preparation for a pushback. Shortly thereafter, smoke was discovered in the vicinity of the overhead bin at row 16. The captain was notified and he ordered that 'occupants evacuate, if there is a fire onboard.' The jetway was brought back to door 1L. The smoke dissipated; thus, the F/A's at doors 1R, 2L, and 2R did not open their doors. However, the F/A's at the other 6 doors were unaware of the situation and continued the evacuation. The ramps at doors 3L and 3R did not inflate and door 5R jammed halfway open. The ramp packs for 3R and 3L were improperly mounted. The 5R pack board was made for a left hand door and the lanyard was not connected to the bottom panel pulley. An exam revealed a ballast for an overhead fluorescent light, PN 69-33C, had overheated and melted the plastic case.