That's very weird
Try this: install service pack 1 for Vista, reboot, install service pack 2, reboot, then do as I said before (copying the text shown by ImgBurn).
Maybe my first post wasn't quite clear...
What about now? Can you see where the newer firmware is?
Using the latest firmware, cleaning the burner's lens and trying all the available write speeds is about all you can do besides using better quality blanks. The other option would be buying a new burner that has better support for your blanks.
The seamless option is only for DVD-Video content (i.e. VIDEO_TS folder) burned on dual-layer DVD media. With BluRay they did away the whole concept of layerbreak and it's all automatically handled by the burner/player.
Post the log of that burn (look in ImgBurn's Help menu) so that we can see if there's anything else that could help.
Why are you using 2.4.4.0 when 2.5.0.0 has been out for ages?
Anyway, the issue you're having could be a buggy storage driver or perhaps a bad filter driver. Look for the latest drivers for your storage controller(s). Use SIW to find their brand/model if you don't know them.
Also post your Filter Driver Load Order (look in ImgBurn's Tools menu).
Firmware isn't the same thing as a driver, and windows only looks for drivers on windows update.
Open Device Manager and look under Storage Controllers: look for the brand/model of your controller in that list and go to the manufacturer's website to get the latest win7 driver for it.
Update your burner's firmware (remove any disc and close the tray before updating then reboot after it's finished) and try again. You might want to try burning at 6x or 8x to see if you get a better burn.
Have you installed win7 drivers for your SATA controller?
Update your burner's firmware (remove any disc and close the tray before updating then reboot after it's finished) and try again with a brand new blank disc at 8x or 12x speed, or at the very least 4x.
Update your burner's firmware (remove any disc and close the tray before updating then reboot after it's finished) and try again with a brand new blank disc. If it doesn't work then try with Verbatim or Taiyo Yuden blanks.
Did you not notice that there's a newer firmware for your burner in the link I've posted above? As for the media, inconsistent quality is exactly the problem with non-Verbatim dual-layer blanks.
Update your burner's firmware (remove any disc and close the tray before updating then reboot after it's finished) and try again. If it doesn't work then use a lens cleaning disc on that burner.
If all else fails then read this -> http://forum.imgburn.com/index.php?showtopic=8000
You could run as admin the program you're dragging files/folders from, or you could put the ISO image(s) in the user's folder (e.g. "C:\Users\username\Documents"), which should give ImgBurn full control over those image files.
Update your burner's firmware (remove any disc and close the tray before updating then reboot after it's finished) and try again. You might also want to try burning at 6x or 8x. If that doesn't work then use a lens cleaning disc on that burner.
It's a good burn + verify so the problem must be with the source file(s). Have you looked in the player's manual? Maybe it needs the video/audio in the mp4 to be of specific formats/codecs.
By the way, if you do a Full Erase on that BD-RE with spare areas disabled (it's an option in ImgBurn's settings) then you'll be able to burn that disc at its rated 2x speed.