something wrong here install problems

[fleamailman]

usual thing, another install on ibm thinkpad x30, changed the source file to feisty, connected internet and the went sudo su, but this is the reply before I could type apt-get update

fleamailman@fleamailman:~$ sudo su
sudo: timestamp too far in the future: Aug 12 20:32:37 2007
fleamailman@fleamailman:~$

should I change the source file to edgy, btw how do I know what version I am running

time is correct time too