Ubuntu – GPG error in Ubuntu update

When I run the sudo apt-get update, it results in the following

 Reading package lists... Done
 W: GPG error: http://ppa.launchpad.net lucid Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY A1715D88E1DF1F24
 W: GPG error: http://ppa.launchpad.net lucid Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 551CE2FB4CBEDD5A
 W: GPG error: http://ppa.launchpad.net lucid Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 1E9377A2BA9EF27F

By googling I came to know the key is missing, and it can be obtained by running the following command with the corresponding hexadecimal numbers

 saikirangvr@ubuntu:~$ sudo gpg --keyserver subkeys.pgp.net --recv 551CE2FB4CBEDD5A

But I was not able to fix this as this gave me the error

gpg: WARNING: unsafe ownership on configuration file `/home/saikirangvr/.gnupg/gpg.conf'
gpg: external program calls are disabled due to unsafe options file permissions
gpg: keyserver communications error: general error
gpg: keyserver receive failed: general error

I tried many times but I was unable to fix. I was behind a proxy server in my college and I have configured the Ubuntu well to use behind the proxy.

After using

 sudo chown -R saikirangvr:saikirangvr /home/saikirangvr/.gnupg

the problem of unsafe ownership was gone, and it gave the following….

 sai@ubuntu:~/gpgpu-sim/ispass2009-benchmarks$ gpg --keyserver keyserver.ubuntu.com --recv 1E9377A2BA9EF27F 
 gpg: requesting key BA9EF27F from hkp server keyserver.ubuntu.com
 gpgkeys: key 1E9377A2BA9EF27F not found on keyserver
 gpg: no valid OpenPGP data found.
 gpg: Total number processed: 0
 sai@ubuntu:~/gpgpu-sim/ispass2009-benchmarks$ gpg --keyserver subkeys.pgp.net --recv 1E9377A2BA9EF27F
 gpg: requesting key BA9EF27F from hkp server subkeys.pgp.net
 gpgkeys: key 1E9377A2BA9EF27F not found on keyserver
 gpg: no valid OpenPGP data found.
 gpg: Total number processed: 0

the result of adding the ppa

sai@ubuntu:~$ sudo add-apt-repository ppa:nilarimogard/webupd8
[sudo] password for sai: 
Error reading https://launchpad.net/api/1.0/~nilarimogard/+archive/webupd8: Couldn't resolve host 'launchpad.net'

same error occurs when using launch pad get keys

 sai@ubuntu:~$ sudo launchpad-getkeys

 Please wait... launchpad-getkeys is running an update so 
 it can detect the missing GPG keys

 Trying to import all the missing keys
 gpg: requesting key 4C9D234C from hkp server keyserver.ubuntu.com
 gpgkeys: key 531EE72F4C9D234C not found on keyserver
 gpg: no valid OpenPGP data found.
 gpg: Total number processed: 0
 gpg: requesting key BA9EF27F from hkp server keyserver.ubuntu.com
 gpgkeys: key 1E9377A2BA9EF27F not found on keyserver
 gpg: no valid OpenPGP data found.
 gpg: Total number processed: 0

 launchpad-getkeys has finished importing all missing GPG keys. 
 Try running sudo apt-get update - you shouldn't see any key 
  errors anymore

What is the problem. *Is there any other method to solve this like through GUI *…….