There's a minor issue with your zshrc's dirstack handling.

I suppose the following should use the index "1", not "0":

    # "cd -" won't work after login by just setting $OLDPWD, so
    [[ -d $dirstack[0] ]] && cd $dirstack[0] && cd $OLDPWD

So the correct version would be:

    # "cd -" won't work after login by just setting $OLDPWD, so
    [[ -d $dirstack[1] ]] && cd $dirstack[1] && cd $OLDPWD

I have found this snippet here:
http://git.grml.org/?p=grml-etc-core.git;a=blob_plain;f=etc/zsh/zshrc;hb=HEAD



Thanks,
Daniel