I am building a formula for a cell on a worksheet by
building it up in a string and then setting the
ActiveCell.formula to that string. The string isn't
really all the large. It looks like this for 5 rows:

=('Segment Rates by CY'!$C$7*$Q$13)+('Segment Rates by CY'!
$C$7*$Q$14)+('Segment Rates by CY'!$C$12*$Q$15)+('Segment
Rates by CY'!$C$2*$Q$16)+('Segment Rates by CY'!$C$2*$Q$17)

When it is complete for 16 rows I get the following error:

Error 7 - Out of Memory.

Any ideas would be greatly appreciated.

Thanks