APEX

I am trying to upload data from a CSV file into a table via the data uploading wizard. However, it always seems to fail on certain rows with an "Invalid number format" error. Even if I paste one of those rows into the wizard, it still fails. There is nothing wrong with the data, and I can do a regular insert in toad with no issues.

The data is:
28126238,101,RM,1/29/2011

The table looks like this:
CREATE TABLE STR_PROD_UPLOAD
(
PROD_CD NUMBER,
STORE_CD NUMBER,
TRAIT VARCHAR2(10 BYTE),
REPL_START_DT DATE
)

This works fine in toad:
INSERT INTO STR_PROD_UPLOAD (
STORE_CD,
PROD_CD, trait, repl_start_dt)
VALUES (to_number('101'),to_number('28126238'),'RM',to_date('1/29/2011','MM/DD/YYYY'));

Anyone have any ideas on what might be wrong or how I can go about figuring out the issue?

FYI - Changing PROD_CD and STORE_CD to a varchar2 fixes the problem, but I would like to know if it is possible to fix this for future reference.

Thx John