Why i cant estimate std coefficients for ARMA terms?

[Amorimneto]

When i estimate a regression using ARMA terms the eviews says:
ARMA terms not allowed in this procedure
Its probably something simple in theory, but i need the why this cannot be done

Att,
Carlos

[startz]

When i estimate a regression using ARMA terms the eviews says:
ARMA terms not allowed in this procedure
Its probably something simple in theory, but i need the why this cannot be done

Att,
Carlos

You'll likely need to show your exact command.