A conflict error on its own just shows that you have a lot of load to handle. So this should not kill the Zope process. But in my experience, CST never worked without problems. Load errors and conflicts happened rather frequently. I'd suggest upgrading to 2.5 and the new session stuff soon, though this might also cause new problems on other parts of the site, and certainly can not be done over night ...
Note that as far as CST (or ZODB in general) goes, load errors are usually bugs but conflict errors are normal. Since Frank is able to run this thing in single-threaded mode and it works ok (it doesn't segfault), the problem is probably with a C extension somewhere that is not threadsafe. CST is all Python code, so I doubt it's that (unless it's calling a library which is not threadsafe, but it uses only the stock Python libraries which we know are). I suspect that it's either some piece of C code in Zope proper or Frank's database adapter. - C