John:

You didn't mention how you are trying to import the file. Are you doing a simple SQL query or a file import? There are several ways you import or add the data into a MySQL database.

I am not sure why you are splitting the data into two parts AND then trying to import as different table names. You could split the data and import into the same table.

Do all the relative tables in the database already exist?

Is this on a Linux or Windows box? Do you use PHP (what version?).

With a little more info I think I could help solve the issue for you.