When a SWF file is inserted as a Flash object, it plays independently of the slide's timeline. As a result, scrubbing through the seekbar has no impact on the SWF object. Generally, this is the behavior you want when a SWF object is interactive. It gives learners the opportunity to interact with the Flash object at their own pace.
To use the seekbar to scrub back and forth through a SWF movie that isn't interactive, insert it as a video instead.