First please do not type in capitals - it is considered as shouting.
The 'shaking' may be because:-
1. the video is a different frame rate to the project - this is most easily seen as 'jerking ' particularly on pan shot
2. the video is interleaved video and is being displayed as progressive video.
A more detailed description of the effect seen eg is the shaking during pan shots or movement, is it horizontal, vertical or both and more details of theproject settings and the video format, frame rate would help.
Videos from videoblocks are usually 29.97 fps. I have downloaded thousands of clips from videoblocks and and this usualy only happens during playback in the time line and it manifests itself more as "jerky" playback than "shaking". (this happens more with the huge .mov files than it does with the smaller .mp4 files). You will not likely get it after you export the file and or burn to DVD If you are using any version of MEP other than MEP 2014, you are going to need to "preview render" the clips after having changed your movie settings to NTSC 29.97 fps and if you have a sufficient amount of RAM and a fairly fast processor, this will dissapeare. If you don't in addition you will need to also change your playback monitor video resolution to something other than "full resolution". This question would have been much easier to answer specifically had you provided your system information and some more specifics about your movie settings (PAL, NTSC and frame rate etc.). Because most videoblocks video clips include no audio that information would not really be necessary.