If you are trying to do a Debian "apt-get update" or equiv. and you get a key issue... try the following commands:
gpg --keyserver pgpkeys.mit.edu --recv-key 9AA38DCD55BE302B
gpg -a --export 9AA38DCD55BE302B | sudo apt-key add -
Note you might need to change the key identifier to get the particular key you are missing!
