CCK Date field cannot hold date "Jan 1 1970"

I am using the Date module with CCK to add a date field to images. The field is defined as type "Date / Text Field with strtotime validation."

I have installed adodb.

If I type in the date as
1970-01-01
I can submit the node without error, but the date is not saved.

If I then Edit the node, I'll see the date field is empty.

But if I type in
1969-12-31
or
1970-01-02
and submit it, the value is saved correctly.

MrB