Linked libraries crash 2.49b in Snow Leopard?

I have a typical project which links to another (in fact, they link to each other), and upon installing OS/X Snow Leopard, I now get a crash upon loading either file. (2.49b)

Any off-the-head ideas?

P. S. I do have the luxury of Time Machine … :RocknRoll: … but I’d like to know how this problem occurred since it did first appear after an OS upgrade.