Cleaning and lubricating the front wheel shafts should resolve the issue. The front wheels can be removed by depressing the small silver nib spring which will be visible through the small gap in the plastic mechanism the top of the wheel fits into. Lift the front of the buggy off the ground, ensure the wheel is straight, then depress the nib spring using a small pen or stick. The wheel should fall off!
Clean the shaft with a rag and then apply silicon based lubricant.