If you can't wait for a bugfix, that's how I "solved":
1. backup of your database (assure it creates instructions on how to create tables and it doesn't keep memory of the auto_increment value)
2. delete the user and the posts tables
3. open the backup files and restore the user and posts tables leaving only the default insert queries (those that create the admin user with your password and the hello world post and page)
NOW
Set up a local webserver and install wordpress, so that you can import your 8 (or more) mb file without any limitation and without uploading it
THEN
Export the posts using the "export" functionality of your local-intalled wordpress: you'll get an xml file that you can use to restore the posts on your remote website.
Hope this can help.
If you have doubts, just ask, I'll check this posts in the next 2-3 days.