I got the following error

Reading package lists... Done
W: GPG error: http://extras.ubuntu.com oneiric Release: Unknown error executing gpgv
executing gpgv

----

W: GPG error: http://archive.ubuntu.com oneiric-updates Release: Unknown error executing gpgv

Then after googling it i found and followed the following but that caused one error

**sudo -i
apt-get clean
cd /var/lib/apt
mv lists lists.old
mkdir -p lists/partial
apt-get clean
apt-get update**

while running i got the error

 "  kapil@ubuntu:/var/lib/apt$ sudo mv lists lists.old
mv: cannot move `lists' to `lists.old/lists': Directory not empty         "

so once again running the update command I got the same error again. Please help me what should i do?