First, you need to describe what kind of video you are editing, so someone may help you with export settings
Read Bill Hunt on a file type as WRAPPER http://forums.adobe.com/thread/440037?tstart=0
What is a CODEC... a Primer http://forums.adobe.com/thread/546811?tstart=0
What CODEC is INSIDE that file? http://forums.adobe.com/thread/440037?tstart=0
Report back with the codec details of your file, use the programs below
For PC http://www.headbands.com/gspot/ or http://mediainfo.sourceforge.net/en
For Mac http://mediainfo.massanti.com/
Once you know exactly what it is you are editing, report back with that information... and your project setting, and if there is a red line above the video in the timeline, which indicates a mismatch between video and project
Along with John's requests, please tell us all about your video camera, and your Project Preset, then the full details of your Export/Share options. There is a mis-match somewhere in there.
ok i dont record using camera's i record what im doing on the screen using Debut. I also exported the video using a custom setting as the other ones left the same effect. This is the spec for it:
Frame Width: 1920 pixels
Frame Height: 1080 pixels
Bitrate encoding: VBR
encoding passes: one
Biterate (kbps) : 5000
I used the same setting when i was using moviemaker and it worked on there. I also tryed using the same clips from the link in the other video and used it though moviemaker and there was no black boarder around the video.
As far as I know, Flash video is not designed to be edited... that is an output file for streaming video on the Internet
I do not know that program, so cannot comment specifically. This ARTICLE covers some tips for working with TechSmith's Camtasia video screen-cap software, so something might be useful of this program, as well - or maybe not.
If WMM handles the material, I'd just use it. If you need more editing power, then Export from WMM (not the Live version) as DV-AVI.
For handling FLV's, no one does it better than Moyea. They have a lot of FLV products.