Strange bug, please help.

[Potross]

Hello. Firstly im sorry if this is the wrong thread. Im new here and this problem has been annoying me for days.

When i log in and start up tekkit classic, as soon as i open my inventory, this happens

http://puu.sh/5TSWa.png

All the blocks turn white/green and i cant get my head around why. In creative mode the blocks stay their original image. When mousing over the layout of the inventory (not where the inventory slots are) all the images turn white. When mousing over a block the original image is shown.

Please help!