Insert Function causes Runtime Error

In OfficeXP when a number of large spreadsheets with
pivots are open at the same time and you try to insert a
function (such as vlookup)inot an empty cell, before you
even get the option to select the function the system goes
into a debug mode and your machine is hosed while it
recovers all of the sheets from the autosaved copy.

This problem can be easily replicated and happens
everytime.

Has anyone else come accross this problem?

Brian