I've been experiencing multiple assertion failure 1910 crashes to desktop in several areas (Planar Sphere, King Strohm's Tomb, Watcher's Keep and others), which I finally tracked down to the animation files d0salfir.vvc and d0salice.vvc added by the quest pack (and used in spells d0salfir.spl which is added onto certain creatures, like icsalfir.cre).
Both these files have the "translucent" and "blend" flags set, but on old (non-BG2EE) this apparently does not work; according to DLTC Editor Pro only one flag can be set and not both. When checking the file, the editor warns that "Transparency+brightest flag causes assertion failure!", which indeed they do. Disabling either flag in these files fixes the problem, I got best results with disabling "translucent" as disabling "blend" leaves a visible square box around the animation.
I'm apparently not the only one with this problem either:
http://www.shsforums.net/topic/57515-assertion-failure-1910/