Thank you very much for the importer. You will run into problems if your [control pane][user albums][Album Picture Storage Type] is set to "Pictures into the file system without direct access to thumbnails" - I had to debug errors complaining about file write permissions however there was no issue with the write, it's that ($vbulletin->options['album_dataloc'] == 'fs_directthumb') was evaluating to FALSE and it was trying to pull my images from the database when they weren't there. The resulting attempt to write a NULL blob triggers the write fail.
Solution - shift album images to the database, then reimport.
I also had to apply the helpful things above after the import - "turn off the category cache in global options" and then "admin => scan database and choice to rebuild the members last photo".
Once that's done, go to your VB [options][User Profile Options] admin and you can disable the VB profile page albums from there now you have imported into PP.