when i try to copy hd video from timeline to usb or sd card say 9 gig on mp4

If the file system on the USB is FAT32, the maximum file size is 4GB.  If you reformat the USB drive to NTFS (Windows) or exFAT (Windows or Mac) you can have larger than 4GB file sizes.

NOTE: Formatting a drive will erase all of its data.

Would you please provide some more information?

What computer system and version of Premiere Elements do you have?

Can you be more specific by what you are using when you write "export hd from time line to usb or hd card"?

What are your project settings and source of the video clips?

What is your output/export procedure?

Can you export your video to your computer's drive and then copy it to the USB?

Please post the name of the program you use so a Moderator may move this message

-A program would be Photoshop or Dreamweaver or Muse or Premiere Pro or ???