It's not a problem as long as there's not already a different Wizard number in there from the reservation process. (You can add a Wizard number if there isn't one, but you can't change the Wizard number in a reservation once one has been applied.)

If you book through a site that has a relationship with Avis, it may insert the site's own Wizard number, thus blocking your Wizard number.

So it would depend on how "aware" of Avis Preferred your company reservation site is.