Impex not remove import data from vBulletin Blog

Impex does not delete imports data of vBulletin Blog, when I delete the import session and all imported data for a clean retry.

It only removes import data from vBulletin:

Impex Help page

Deleteing Impex Session.

Session deleted

Deleting imported data from moderator .......Completed

Deleting imported data from usergroup .......Completed

Deleting imported data from ranks .......Completed

Deleting imported data from poll .......Completed

Deleting imported data from forum .......Completed

Deleting imported data from forum .......Completed

Deleting imported data from user .......Completed

Deleting imported data from style .......Completed

Deleting imported data from thread .......Completed

Deleting imported data from post .......Completed

Deleting imported data from thread .......Completed

Deleting imported data from smilie .......Completed

Deleting imported data from pmtext .......Completed

Deleting imported data from avatar .......Completed

Deleting imported data from customavatar .......Completed

Deleting imported data from customprofilepic .......Completed

Deleting imported data from post .......Completed

Deleting imported data from attachment .......Completed