Vanilla Ice's Co-Star Bucked From Horse During Polo Lesson (Video)

There was a problem. Ice did not solve it ... instead the rapper watched helplessly as his friend was bucked off a horse at a polo practice ... and TMZ Sports has the video.

Ice was shooting for his reality show "The Vanilla Ice Project" and trotted out some horses at the Grand Champions Polo Club in Wellington, Florida so he and his friend Wes Kain could learn how to play.

But while Ice was shooting a selfie video, Kain got the heave-ho from his horse ... and rolled off the back of the animal.