[PyMOL] Fwd: loading amber files and selecting traj frames

Hello Pymol Users. I just started getting into Pymol and encountered two 
issues I'd like to ask about.

1. When trying to load amber topology and coordinate files that do not 
have the default extension, I get this error:

    PyMOL>load ../Cdp_UCM.prmtop, CDP, 1, top
      ObjectMolecule: Attempting to read Amber7 topology file.
      CmdLoad: "../Cdp_UCM.prmtop" loaded as "CDP".
    PyMOL>load ../Cdp_UCM.rst7, CDP, 1, rst
    CmdLoad-Error: must load object topology before loading restart file!


If files have the default extension and I don't need to to specify the 
file type, loading works fine:

    PyMOL>load Cdp_UCM.top, CDP, 1
      ObjectMolecule: Attempting to read Amber7 topology file.
      CmdLoad: "Cdp_UCM.top" loaded as "CDP".
    PyMOL>load Cdp_UCM.rst, CDP, 1
      ObjectMolecule: read coordinates into state 1...
      CmdLoad: "Cdp_UCM.rst" appended into object "CDP".
      CmdLoad: 1 total states in the object.

Of course I can work around this by modifying the extensions on my files 
before loading, but due to compatibility issues with other scripts I'd 
prefer to leave the extensions I've been using heretofore.

2. When using the load_traj command is there a way to select which 
frames are to be loaded? For example to load only every 10th frame?

Pawel