When using DoCmd.OpenForm, to open one Form from another, as you're doing (a Switchboard is just a simplified Form) you have to use the syntax
DoCmd.OpenForm "YourFormName", acFormDS
to open the Form in Datasheet View...even if Datasheet is the Default View!
If, as June7 guessed, you are, in fact using the Switchboard Wizard, it doesn't use this parameter in the syntax for either of the two choices it gives you, for opening Forms.
The Switchboard Wizard is very rigid in how it does things, such as opening Forms, which is why very few experienced developers use it; most of us simply 'roll our own,' using a standard Form.
Linq ;0)>
The problem with making anything foolproof...is that fools are so darn ingenious!
All posts/responses based on Access 2003/2007