user directories can't be accessed with automountd

Managers,

I'm having problem with the automountd(5.1 release) where user logs in
and their home directory is not mounted for a few minutes.  if user
explicitly cd's to home directory(full pathname) then their directory is
mounted.  

problem--> logging in doesn't alert the automounter to mount user
directory; but if user cd's to full path(after login), then automounter
is alerted to mount user directory.

does anyone know if there is a fix for this? all the yp configuration is
exact and correct.

any help is greatly appreciated.

Susan James