I have the Debian distribution of Linux. When I type xdm as they suggest i get the "command not found" message although I can clearly see the binary in the directory. I checked to see the file attributes and they are set to be 755 so I don't understand what the problem is. When I try running startx it also gives me the same error although I can see the the startx binary as well. What's going on? thanks for your help.