load single space into the table's field in Oracle(load opt)

[mansoor_nb]

Hi all,
I am extracting the data from teradata and loading into the oracle. the mapping is quite simple and it is one to one mapping but the data involved to be written into table in Oracle is huge and that's why i am using the Bulk load options. I have to pass single space into one of the field of the table in Oracle DB. I have set the env variable $APT_ORACLE_PRESERVE_BLANKS to true and also i have used the env variable $APT_STRING_PADCHAR. But all the records are getting rejected giving the error reason as "Cannot insert Null values into field Event(field name)". The field name is non nullable and i think it should accept single space while loading into the table.
When i tried with the upsert option, the records are getting inserted into the table.

Please provide your thoughts on this so that i can proceed with the suggestions provided by all of you.

[ray.wurlod]

What is the data type of the field? To what value did you set APT_STRING_PADCHAR environment variable?

[mansoor_nb]

The data type of the field is Varchar2(50) and i have tried with 0x20 and 0x0 for APT_STRING_PADCHAR