I've noticed when installing Dolphin 7 via Softaculous and you fill in your RMS settings there's still an issue when uploading videos.
The video displays as 100% complete but it fails.
If you get this you need to change the permissions for the ffmpeg file
Navigate to flash -> modules -> global -> app
The default permissions are set to 644, so hopefully this will solve the issue.
This was the first time i had this issue since it's been integrated into their software.