checkout on an empty directory fails

I have a clean derectory ang the git database. Now I want check out the master. The master is the last commit. The files name are displayed but not stored out in directory.

Why can not I  check out?

René Doß

red@linux-nrd1:~/iso/a> ls -a . .. .git red@linux-nrd1:~/iso/a> git checkout master D SP601_RevC_annotated_master_ucf_8-28-09.ucf D rtl/ether_speed.vhd D rtl/ether_top.vhd D rtl/ether_tx.vhd D rtl/takt.vhd D sim/makefile D sim/tb_ether_top.vhd Already on 'master' red@linux-nrd1:~/iso/a> ls red@linux-nrd1:~/iso/a>