Hello Peter,

I use VMWare Workstation 6.5.2 to do my xl2007 testing

In one session I have Vista and Excel 2007 SP1
This produces the expected result as follows
?application.version, application.Build
12.0 6214
=SERIES(,Sheet1!$A$2:$A$4,Sheet1!$B$2:$B$4,1)
=SERIES(,Sheet1!$A$2:$A$4,Sheet1!$C$2:$C$4,2)
=SERIES(,Sheet1!$A$2:$A$4,Sheet1!$D$2:$D$4,3)

=SERIES(,Sheet1!$A$8:$A$12,Sheet1!$B$8:$B$12,1)
=SERIES(,Sheet1!$A$8:$A$12,Sheet1!$C$8:$C$12,2)
=SERIES(,Sheet1!$A$8:$A$12,Sheet1!$D$8:$D$12,3)

In another session I have Vista and xl2007SP2. Here's what I get
?application.version, application.Build
12.0 6425
=SERIES(,,,1)
=SERIES(,,,2)
=SERIES(,,,3)

=SERIES(,,,1)
=SERIES(,,,2)
=SERIES(,,,3)
If I step through the routine slowly in the debugger is runs ok and
prints the expected result.
If I step through it quickly there will be some, but not all, of the
empty arguments.

This is really weird.
This weirdness is not unique to my computer.
It is quite definitely happening to at least two of my customers.
It seems to be unique to xl2007 SP2.

Brian