using "call" for packaged procedure?

After moving a procedure into a package I discovered I can no longer use "call" to invoke the procedure.

Can someone explain why this is?
Many TIA!

old code:

    call p4_add(:typeid,:reposid,:depotFile,:rev,:tmstamp)

new code (broken):

    call p4.add(:typeid,:reposid,:depotFile,:rev,:tmstamp)

    ORA-01747: invalid user.table.column,table.column,

               or column specification

new code (works):

    begin p4asset.add(:typename,:repos,:depotFile,:rev); end

--
Mark Harrison
Pixar Animation Studios