This is generally due to lack of memory allocated to your hosting account or the memory limit you have set for the wordpress installation. You can contact your hosting provider for this. Meanwhile, you can try importing couple of more times, and the missing pieces should get imported. So I would suggest that you retry importing the data and check whether you’re successful in importing the missing sections. You may have to delete the duplicate menu items though. Pls have a look at this for more info on setting the memory for your wordpress installation –
If you still face the problems, then please send me a private message with a temporary login to your WordPress installation and I will fix the issue. Thanks!