Utl_File error

I have an utl_file that reads data from text file into an oracle database.
the problem I am having right now is if I have three records in the text file I am reading from, my code works fine but if I have more than three records in the file, I get a PL/SQL error which says:
ERROR: -6502-ORA-06502: PL/SQL: numeric or value error: character string buffer too small.
I originally set the string buffer to 100. eg.
strbuffer VARCHAR2(100); -- input file.
I changed the size to strbuffer VARCHAR2(2000); -- input file
I still get the same error.
How can solve this problem.
Thanks in advance.
simflex

UTL_FILE.FOPEN (
location IN VARCHAR2,
filename IN VARCHAR2,
open_mode IN VARCHAR2,
max_linesize IN BINARY_INTEGER) <<<< Is this Oke
RETURN file_type;