I need to know how and why catia is crashing while working with windchill on winxp

I need to know how and why catia is crashing while working with windchill on winxp

I am working in a production environment on a Catia application and windchill workgroup manager client 9.1 with Windows XP SP2 on an HP XW9400 workstation with 4GB RAM and NVIDIA Quadro FX 4600 graphic card.