I have never seen that error, but trying to restore a course from v1.9x to v2.7 cannot be done.
You need to download and install a v2.2.x, restore the course to that, then back it up again, then try the v2.7 restore.
You can get the v2.2.11 from the Legacy Downloads area. If you do not have a server available, then you can start with Xampp. Download the version that suits your computer or laptop and follow the installation instructions carefully. Unzip the Moodle and copy it to the [drive]:path\to\xamp\apache\htdocs\moodle2211 directory/folder. (add the moodle2211 to the htdocs directory). You will have a fully functional web server, localhost, and then you can install a v2.7.x and you will have a functional, full featured, test Moodle if you want. I suggest you do this anyway.
Why would you bother with this run around? Simple, the database of v1.9 is very different from the database of v2.7. Too different for any attempted restore to work. You may have to install a v1.9.19+ as some of the backup structures of v1.9.19 were a little more closely aligned with v2.x which made conversions to the v2.x format a little easier, and more oportunity to succeed...
EDIT: I am not a big fan of Xampp, but it is easy to get started with it. If you don't use the Moodle for much more than testing techniques for building courses, try out or test new, to you, plugins, blocks or other features, Xampp does its job and works well. If you want to use it for more than that, then I suggest you build your own Apache web server, adding PHP and MySQL. These are all downloadable, free, and relatively easy to install and configure, but read the instructions carefully for MySQL.