Hi Dave,
If your site doesn't use or doesn't have the search box, which usually comes included in some skins, then you can add:
TRUNCATE TABLE {objectQualifier}SearchItemPosition
in that script right after
TRUNCATE TABLE {objectQualifier}SiteLog
This will clean up that table.
But on top of that you should also deactivate the Search Engine Scheduler cause if you don't, that table will grow again.
BTW, I think the table name is "SearchItemWordPosition", not "SearchItemPosition"
Best regards,
Aderson