I just ran into the exact same problem on my fresh 2.6 install and my backup file is even smaller than yours. My env. is as follows:
SQL Express 2012
PHP 5.4 (since there aren't any MS SQL drivers for 5.5 yet)
I would get to the point to where I would click the 'perform restore' button and it would chug away for a while until it would finally time out. After the time out, I would go back to the home page and the course would be there. I have a few documents and hyperlinks in the primary module of the course and then also had 7 'topics'. The topics each have a quiz in them. The topics showed up but were titled Topic 1, Topic 2 etc with no quizzes in them. So then I decided to try backing up just the quizzes and restoring them using the 'merge' restore function and VIOLA! Worked like a charm and only took 15 seconds or so.
Not exactly sure what is going on in 2.6+ but I've read several posts now about problems with restoring courses. Hope this helps you out.