SD/MMC From the ground up

Hello all,

i am new here. I have a Ardduino Duemilanove Board. It worked very fine till now. I built a Ultra Sonic distance measurement and a lcd display. But now I tried a SD Card Shield from seeed Studio.

I tried the code

microfat2::walkDirectory(showDirectory_walkerfn, &count);

Serial.println(PSTR("\n"));
Serial.print(count, DEC);
Serial.println(" files found.\n\n");

And the response is 0 files found.

But I formated the SD Card. I put one File with a smal Text in the file.

What can be wrong ?

Frank