Hmm the only thing I have close to an SD card is a Flash drive in the USB port...
However, I am also getting this same error, i did a test on some random text file... but when I created a subfolder, it worked perfectly. It seems this software is not exactly supported for placing files within the root folder of any Drive, Hard drive, Flash drive, network drive, sd card, external hard drive. Because I just tried it on an External Hard Drive that I assigned to letter F.
Path -> "F:\"
"F:\ is not a valid Folder - please correct or clear."