When i play the video preview, it shakes from top to bottom, and starts to blur and unblur, what do i do?

Please follow the directions in this sticky, so that users can see the technical details of your video: www.lwks.com/index.php?option=com_kunena&func=view&catid=23&id=66072&Itemid=81

here is a clip of it, turn down your volume

My guess is, you've clicked once next to 'Playback format' of the timeline menu and switched to an interlaced playback format.

Instead of relying on my guess, however, the mediainfo would be surely helpful. Here you'll find a short description including a valid link to the app Mediainfo:

www.lwks.com/index.php?option=com_kunena&func=view&catid=27&id=235619&Itemid=81

I will get mediainfo, but just asking, how would i change the playback format off of the guess you've made?

In EDIT mode, right-click on the timeline and check 'Sequence Commands.Playback format'.
If it's interlaced, e.g. 1080i, switch to a progressive format, e.g. 720p.

I redownloaded it and it works fine now, thank you!