Hey, I just noticed that I hade the same problem when using the app store, I had already purchased OS X Lion through the app store, when I went into my purchases it had an update button next to my purchased Lion file, when I pressed it I was prompted to enter the password for "atthegeek@gmail.com" account as well... the exact message was:
You have updates available for other
accounts
Sign in to atthegeek@gmail.com to update
applications for that account.
Also very concerned if this is some form of malware, trojan, DNS attack, virus, etc...
Please, anyone who can provide us with some information about this and how to remove/clear up the problem ASAP it would be greatly appreciated.