Combining animations in spreadsheet

I have data with a MathType like:

(Time -> ((lat, lon) -> value))

I would like to be able to do a combine on multiple cells like this in
order to produce animations.  When I do so I get the error:

could not evaluate function "combine"

Is there any way to make this work?

I am working on an educational application that uses the VisAD
spreadsheet.  What I would like to be able to do is have many cells of
data at different time periods and allow students to assemble their own
animations.  The data files I import to VisAD are serialized VisAD
objects.  Each one has a Linear1DSet consisting of 1 element associated
with time.  The spatial data are mapped using a Linear2DSet.