Digital camera images not downloading.

I have recently returned from Italy with around 333 photographs on my digital camera. These are stored on a 512mb SD card.

I have a slot on my PC for the card so I have downloaded the photogaphs - or so I thought. Only 206 are visible when viewed. The others show up as files but when I try to open them in Adobe Photoshop it tells me I cannot "because an unknown or invalid JPEG marker type is found".

If I put the SD card back in the camera all the images are visible. Any suggestions?

Just some searches:

http://www.dogpile.com/info.dogpl.to...eg+marker+type

http://www.google.com/search?q=an%20...e%20is%20found

http://groups-beta.google.com/groups...r=&sa=N&tab=wg