[donB]

If you're trying to use the folder inside the directory ~/, login as root. Although its not recommended to use root. Better change the directory to something else, say - /home/ubuntu/samp03/.

Also, make sure you got all the server files inside the directory. If you're running a 64 bit OS, check if the libraries are installed accordingly. Did you change your RCON password, as the default "changeme" prevents the server from starting.

BTW, do activate your Windows version soon.