Because only the 6.4 structure is supported by the vbulletin importer.
Reason:
I just learned that Infopop knew about serious security issues for months, the oldest reference I could find was April, and not even now, that beta2 is out, *any* email alert whatsoever.
Couldn´t be the beta status, because I´m feeling like a public beta tester for some time now.
Couldn´t be the raised system requirements - php 4.1 - that build is 3-4 years old. It´s not like php 5.0 is required.
I have been very patient regarding development, I understand that staff is short in numbers and even that´s ok with me, but this is grossly negligent.
In the end, to end the ranting, I´m very interested in the new VB 3.5, which introduces "hooks", so you can write hacks without modifying the source.