Migrated blog, now 'Edit post' link no longer appears

I look after an existing wordpress install with about 500 pages and 100 posts. Recently I was asked to make a duplicate of this site on a subdomain of another site. So I exported from the original site and imported the xml file on the new site. All the plugins are the same. The new site works as expected, except for one thing …

On the new subdomain site, the ‘Edit post’ link no longer appears. The templates are identical on both sites.

Any clues what could be causing this? Thanks.

PS The old site is sunning 3.4.1, the new one is 3.5.1.