Bridge CS5 won't preview XDCAM-EX .MP4 files

Running new install of Bridge CS5 4.0.4.2 on Win7 Professional 64-bit.  Can't preview Sony EX1R (XDCAM-EX) .MP4 files.  If I associate .MP4s with QuickTime I get "the movie contains some invalid data".  If I associate to Windows Media Player I get "Windows Media Player cannot play the file."

The .MP4s go fine into Premiere CS5.

Any thoughts?

TIA,

Bruce...