I had the same problem here. Strangely, when I put my tables in the same DB as WordPress, the problem disappears.
On another instance of my installation changing everything to the newest releases (MySQL -> MariaDB, PHP, WordPress itself) solved the problem too. In this setup I did not put the tables into the WordPresss instance and left it in its own database. MariaDB seems to work differently.
Why all this happened: I do not know…
Sorry, above comment from my side is obsolete. I made it working. I forgot to fill the field “How much comparisons per Server-Request?”
Exactly the same issue here.
I have a fresh WP installation 3.8.1 with just the default plugins including Akismet enabled. Language in WP switched to german. The installation is on a Synology NAS.
Importing the same file on smackcoders demo site works fine.
