First of all debug your code, you will sure resolve your issue by yourself.
I don't know PHP but I have a doubt
Your insert statement does not contain actual values of a variables. It is just a normal string that you are passing to execute.
$query12= "INSERT INTO student_info(Fname, Lname, email, phone, stuid, stupass,"
. " bankname, accname, iban,authorize,Bcountry,other) "
. "VALUES ('$sFname', '$sLname', '$semail', $sphone, '$stuid', '$stupass', "
. "'$sbankname', '$saccname', $siban, $sauthorize, '$sBcountry', '$sother')";
There are variables like
'$sFname', '$sLname'...
etc
From where you are passing values to a variable.
From where your insert command will find the exact values which are you are filling in the variables ?