Problems with rotation

About six months ago I made an animation and at the end of it there was supposed to be a rotation which I had done plenty of but in this one I couldn’t get it to rotate the correct way. It was transforming at the same time if that has anything to do with it but when I had to submit it (it was an assignment at university) I still hadn’t solved it. I showed it to the tutor and he couldn’t solve it either so fortunately he didn’t mark me down but now I want to submit it on a CV so I need to solve it. I tried rotating it on all the axis and it still just rotated in the same direction so I don’t know what else to do. I’ll try to have the code up later (as soon as I dig it out) but until then has anyone got any ideas as to what it could be? Help appreciated.

Could give a little more details on the object and how the rotation should go?

Also a little of the code where you rotate the object?

One guess could be problem with Euler angles.