Amy Winehouse was at a loss for words when she won the Artists' Choice Award at the MTV Europe Music Awards.

The 24-year-old British singer-songwriter -- wearing a short, cleavage-baring denim dress and her signature beehive hairdo -- was struck speechless while accepting the award before a cheering crowd. All she could muster was "um" and "thanks" before leaving the stage.

"She clammed up, she had a moment there and didn't say anything (on the microphone), which is a little sad," R.E.M. singer Michael Stipe, who presented the honor to Winehouse, told AP Television News after Thursday's event.

Winehouse later performed "Back to Black," a song from her acclaimed album of the same name.

The retro soul singer ran into trouble last month when she and husband Blake Fielder-Civil were arrested in Bergen, Norway, on charges of marijuana possession. They were released after paying fines of $715 each.

Her lawyer said Thursday that Winehouse is appealing the fine because she didn't understand that under Norwegian law, accepting a fine is the same as pleading guilty, which could have serious consequences when she seeks to enter the United States.

Winehouse canceled an appearance at the 2007 mtvU Woodie Awards, which will be presented Thursday in New York, because she cannot travel to the U.S. "due to visa issues."