Try adding a space between CD and the path. If that does not work try the command chdir instead of just cd (it is the longhand form). I suspect it is just the space you are missing... Assuming that is the only issue the commands should be:
cd \ <enter>
cd \i386 <enter>
expand pci.sy_ C:\pci.sys <enter>
C: <enter>
cd \ <enter>
copy pci.sys C:\windows\system32\drivers <enter>

Hope this helped...