Hi there,
try to reinstall your facebook application. You can download from playnow, the problem that you are getting it looks that the application has not been installed correctly.
After you reinstall your application try to access it by wi-fi instead of pre-paid internet and test it if works, if does then try next step but before close down the facebook application.
Then you can try to connect by pre-paid internet if the application in case closes again then there is something wrong with your network on this case you should contact your network provider.
Good luck
Stagroz
