Getting a full page screenshot?

Hi

I'm getting following error if i use the above give code for screenshots in telerik, Can anyone please help me

System.Runtime.InteropServices.ExternalException (0x80004005): A generic error occurred in GDI+. at System.Drawing.Image.Save(String filename, ImageCodecInfo encoder, EncoderParameters encoderParams) at System.Drawing.Image.Save(String filename, ImageFormat format)

when i googled about this error, it says the issue is with  the folder access , but i checked there are no access issues with the directory,

Thanks,

KM