When I run SD-Flasher.exe as administrator using win7, I cannot relayout
the SD card.

Error Message as below:

Relayouting, please wait...
Relayout Disk 1 Error(Readonly Media?)
1 Total, 0 Succeeded, 1 Failed

Can anyone help?

I have used external card reader and tried SanDisk 2G, Sandisk SHDC 16G