Main reason it does that to me is when I'm mdding it and I exced a table limit (ge the expansion zip) or there is a texture missing (get rid of last model used) or weapon prob (check your parsing and reuse previous saved WORKING tables (keep a good copy in a folder to cut and past for recovery)
That's as helpful as I can be...
Good luck pilot... (Edited, no lights on hit i instead of u

)
BTW if someone has a working model of the Xanthus class ship please send my the .pof and textures... I only got the beta somewhere and it is buggy. I heard it was released but never found the link... Thnx.
Oh and Ryx's carrier has 1 bad texture FS2 is unable to open. Don't know if it is the .pof or the map itself.