Unless the application uses a nonstandard method for getting input(or blocks it explicitly, which I assume they would have told you), it should work.
What is your command target set to?
Note that this can be affected by the following:
- The "Send commands to :" dropdown on VoiceAttack's main window
- The "Send commands to" checkbox and dropdown in the profile options menu
- The "Send this command to" checkbox and dropdown in the "Edit a Command" window"
- The "Perform a Window Function" action with the "Set command to target this window" checkbox checked
Have you tried holding down keys longer(I.E. increasing the "Hold down for X seconds" value)?
If you send keypresses to notepad, does that work?