All textures are black-white :(

[schachteana]

..and all players around me are stuck in the ground.

What could I try to do different? So far, I've un/checked "load ressources at once" and "force safe mode".

Running system: Latest Ubuntu Mint 17.1, 64Bit
4 cpus, 900 MHz (at least lscpu tells me so)
6 GB ram
graphic card: Intel 2nd gen core processor family integrated graphics controller (rev 09) VGA controller (whatever this is meant to be)
(laptop)

on Windows7, it had been running just fine.

Any help would be very much appreciated