Oh, dear, no response. I was hoping to find an answer to this myself. I got in a Seeeduino Mega about a week ago and have yet to get it to accept any of the usual Arduino getting-started loads. The Arduino sites suggest there’s some problem with the automatic USB driver, and a need to manually load the correct driver, but the instructions don’t seem to match what the Seeeduino Mega does.
I get the impression the computer itself probably is running, but the USB link doesn’t sync right. The SeeedStudio wiki pages have never been set up.
Combined with them sending me a Grove Differential Amplifier that was nothing like the one described on the Wiki (they posted a changed design 3 days later), I’m thinking I made a terrible mistake going with SeeedStudio. Probably ought to scrap the thing before I get in any deeper and just buy Arduino.