When the page loads all rotator items are shown for a few seconds and are then hidden.

In some cases all rotator items are displayed on screen for a few seconds when a page containing the content rotator module for DNN first loads. To prevent all items being shown when you first open the page add "overflow:hidden" to the "items" class in you css. Also make sure the height of the "items" div is equal or smaller than the actual items.
After this is implemented only the first item will be visible.