Hi Jafo,
I recently tried the plugin and although I thought it was working it appears to have problems importing users from VB to WP. Everything is activated, user mapping was done first before activating it. However if someone logs into the forum, then tries to view the main page they get an error message, which is essentially because they're not a user on the website.
Fatal error: Cannot redeclare get_users_drafts() (previously declared in /homepages/10/xxxxxx/htdocs/wp-admin/includes/user.php:233) in /homepages/10/xxxxxx/htdocs/wp-admin/admin-db.php on line 3
I do have a prefix on the VB tables but I believe this was fixed in version 2.03 of the plugin (I have 2.06). I'm tried uploading the plugin again just incase but without luck. I've deactivated/reactivated the plugin and redone the options from step 1 with any luck either.
Any suggestions? the cookies works for me (as I'm a user on both) without any issues.
WP and VB are both running the most up to date versions and share the same database. If I post in WP it adds it to the forum etc without any issues, it's purely the user transfer that isnt working.
I'll try changing the settings for prefix etc and see if I have any luck, user mapping etc appears to be setup fine.
The website forum in on the same domain simply in the \vb directory.
If a user registers in VB and I insert the same username/password in WP they can use the WP section as normal - cookie seems to work fine. It appears now to be purely the user not coming across automatically form Vb to WP.
yet another edit:
I've just checked that vbb_VBION is set to 1 in the wp_options table

I was hoping it was that!
I started at the beginning of the comments on here and read them all, right near the end what do I find? It's not actually compatible with WP 2.3 (which I have). I'm guessing my problems might well come from that

I'll wait and hopefully we'll get a new compatible version