Cannot open .m2v in Adobe Encore

[Sugar]

I have got this .m2v file in 16:9 letterbox format. I can load the asset in Encore but when I click on it to put it onto the timeline, Encore blocks.

I have multiplexed the file with the audio stream. The .mpg file plays fine with Windows multimedia player.
Again I can load it as an asset in Encore but the software freezes when I click om the asset.
First time this is happening to me. I played with the setting to change from video 4:3 to 16:9 but no luck.

Any idea how to fix this?

[troyvcd1]

make sure it is 720 x 480.

[Sugar]

It is 720x480.

I managed to open it using the following procedure:
- I loaded the asset, saved and closed the project,
- In Windows Explorer, I renamed the asset,
- I reopened the project in Encore DVD. The name o the asset was in italic. I put it on the timeline.
- In windows explorer, I renamed the asset to its original name,
- Encore DVD re-opened the asset and the video appeared in the monitor.

The problem is that when I started to build the DVD, it says this is a non-compliant file and yet it is a compliant file.
It may come from the fact that I indicated the video was in 16:9 when it is in reality 16:9 but reformated to fit in 4:3.