The cause of this problem isn't known. However, there are several things that you can try that worked for other people with the same problem. First, you can disconnect from the Internet, then go to Settings -> Applications -> Manage Applications -> All, select the Google Play application and tap Clear data. After you did this, try removing your Google account and then add it back in. To do that, you can try going to Settings -> Accounts and sync, tap on the account and then select Remove account. If you have more than one account try removing all of them. Reboot your device and try again to update your Facebook application.