I have no idea what t_delete is but it seems to be dying in your malloc library. Assuming it's not out of memory, you'll probably need some kind of malloc debugger (like efence) that can detect heap corruption.
Hmm, yeah. Out of memory is unlikely; the core is only a couple hundred MB on a dedicated 2GB box. t_delete is in the depths of the Solaris malloc implementation. I'll ask Sun if they can make anything out of "malloc(35)" causing a SEGV; doesn't exactly sound like documented behavior.
You're right that without a memory debugger it's tough to trust any of this. But it's also tough to run a memory debugger in production...they generally slow things down a bit more than I'd like.