I'm guessing you had 'infinite' lights in Poser, these get translated into 'sun' lights for Lux now.

You probably want to change them to either 'spot' or 'point' lights in Poser; or just remove the 2 additional suns so you only keep 1 sun. :)

Software: OS X 10.8 - Poser Pro 2012 SR2 - Luxrender 1.0RC3 - Pose2Lux
Hardware: iMac - 3.06 GHz Core2Duo - 12 GB RAM - ATI Radeon HD 4670 - 256 MB