Issues importing pages; Need Templates Installed and infobox setup.
Fragment of a discussion from Project:Support desk
See Manual:Performance_tuning. Enabling caching is probably the most important thing you can do in terms of speeding site up.
When importing files, it is significantly better to import via command line instead of web interface (if possible). The error you're getting indicates your site is too slow. If you have access to your php.ini you can increase the time limit.
