mysqli_real_escape_string error

Hi,
I am getting a “Warning: mysqli_real_escape_string() expects parameter 2 to be string, object given in C:\Software\xampp\htdocs\fp\wp-includes\wp-db.php on line 1102” when using the front end to upload a csv.

I have no serialized data in my csv.
A sample is given below.
Username,Email,first_name,last_name,program,display_name,student_id
test218,k*****@****.**,Ss,Kh,SSW,Ss Kh,21212121
test219,k*****@****.***,Test,Khan,CDW,Test Khan,12121212

Do you have any experience what this might be…
Thanks In advance.
Khansadi