Be aware that your formula is not referring to D4 and D5, but to A6 and B6. Are any of them #NAME?
I assume that you have Analysis Toolpak ticked in your worksheet Add-ins menu, not (just) VBA

--
Kind regards,

Niek Otten
Microsoft MVP - Excel

"jamesp@premiercs.co.uk" <jamesppremiercscouk@discussions.microsoft.com> wrote in message
news:01147221-32FF-47E3-B2D5-6F30A2B131FD@microsoft.com...
| Sorry Niek doesn't work. In my experience .value and .formular1c1 work the
| same
|
| James
|
| "jamesp@premiercs.co.uk" wrote:
|
| > I am using VBA in MS project to enter information into Excel 2003. It
| > creates an instance and enters various dates. However if I put the
| > Newworkdays function into a cell (e.g. xlApp.range("D6").value =
| > "=networkdays(rc[-3],rc[-2])" where D4 and D5 are recognised dates I get the
| > #NAME? error message. The Add-ins for the Analysis toolpak have been ticked.
| >
| >
| > I tried running code to turn the analysis toolpak off and then on
| > programatically but still the same error message
| >
| > Any ideas how this can be fixed?
| >
| > Many thanks
| >
| > James