Preview Access report from Vb app.

I want to preview and print a Access report from a VB 6 aplication.
If a use
DoCmd.OpenReport strRapport, acViewnormal
The report print okey. But if I write

DoCmd.OpenReport strRapport, acViewPreview

Nothing happens.
Why dont I get a preview of the report ?

all help is wellcome

Thanks in advance
Calle