YES, you should use that function to ALL inputs made by user, which you are going to store in database.

in new version the new function is
mysql_real_escape_string() which is recommended to use, but, you have to make sure if it exists in your version or not
or you can do this

$var = (function_exists('mysql_real_escape_string'))?mysq l_real_escape_string($user_info):mysql_escape_stri ng($user_info);

its jsut saying if that function exists then use that else use other one

ABOUT THE ERROR
please specify the line number where error occured

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