Go to Preferences, set Launch to Factory Scene in Document tab. Or, you may uncheck Use external binary targets in the Misc tab. Or, select Launch to Factory State in the Interface tab.
Update: It seems that when you launch the Libraries Window and quit the application, the problem persists. I'm going to look into this further...
Last Update: The problem has been finally solved by upgrading Poser Debut to version 10 (Hey, it's sale today in TUAW: Poser Debut Sale). In case you're wondering, I'm using Mavericks (Latest Mac OS). The previous version of Poser Debut is 9, and it works in Lion without crashing bug.
