Precompilers, OCI & OCCI :: ORA-01002 / Fetch Out Of Sequence

I am back with one more issue. I am fetching records through a cursor from database using Pro*C and inserting some records as shown below:

EXEC SQL DECLARE cur_num CURSOR FOR
SELECT STUDENT_NUMBER
FROM STUDENTS
WHERE STDID = :temp_num
ORDER BY STUDENT_NUMBER;
EXEC SQL OPEN cur_num;
EXEC SQL WHENEVER NOT FOUND DO break;

[code]....

This code works fine sometimes but ends up with this error sometimes: ORA-01002: fetch out of sequence and also do I need to do null termination once i fetch data from the database like this:

Quote:EXEC SQL FETCH cur_num INTO :std_num ;
std_num.arr[std_num.len] = '�';
std_num is declared as varchar datatype.