Undefined function format in expression

I wish to format the date of a Date/Time field in a query
for display purposes on a graph.

Whilst things work fine on my machine, when I port the
application to another machine, the query gives the error
message:-

"Undefined Function Format in expression"

In fact the other machine returns an error with and
expression using Format(). What setting controls this so
that I can change it on the offending machine?

My machine runs Access 2000 (Office 2000 Premium) on NT4
The other machine Access 2000 (Office 2000 Pro) on Win2000

My row source SQL says:-
TRANSFORM Count(*) AS [Count] SELECT (Format
([edDateTime],"mmm"" '""yy")) AS MYDATE FROM [qryStats]
GROUP BY (Format([edDateTime],"mmm"" '""yy")) PIVOT
[qryStats].type;

My resulting expression in the Expression Builder:-
MYDATE: (Format([edDateTime],"mmm"" '""yy"))