just a word : if you speak about pre and post command in options of arcserve, I think you can't run it on other servers.... it allows you to run command on arcserve server but not on another server (i have try it but it didn't work... but i'm not an example, nothing work fine with arcserve 9....)
to test, try to launch a command (like edit) : if it works, your shutdown will be ok!