Check the resolution of the recordings. 1280x1024 is not a widescreen (16:9) format, but the older "TV" (5:4) format. So, for example, if the recording is using 720p (1280x720) resolution, you'll end up with black bars at the top & bottom of your screen.
It could also be that for playback it's not "stretching" the videos. For example, if your recording was set to 960x540 resolution (still a 16:9 ratio, but not a common resolution), & your monitor is displaying it in a "windowed" view (i.e. your monitor is still displaying at 1280x1024 resolution, which is larger than the video resolution), you'll end up with black bars on all 4 sides.
Unfortunately, ReLive is fairly new, & I haven't tried it myself, so I don't know for sure if...