Você parece estar usando o modo SFTP em vez do modo SCP
Tente mput *.pgp
(um palpite baseado em comandos FTP)
O manual diz que os curingas devem funcionar
put <file> [ [ <file2> ... ] <directory>/[ <newname> ] ]
If only one parameter is specified uploads the file to remote working directory. If more parameters are specified, all except the last one specify set of files to upload. The last parameter specifies target remote directory and optionally operation mask to store file(s) under different name. Destination directory must end with slash. Filename can be replaced with Windows wildcard1) to select multiple files. To upload more files to current working directory use ./ as the last parameter.
…
put *.html *.png /home/martin/backup/*.bak
Você DEVE colocar o diretório de destino como o último item no comando citado.
d:\winscp\winscp /command "option echo off" "option batch on" "option confirm off" "open sftp" "put D:\*.pgp ""C:\Documents and Settings\newtowinscp\Documents\Backups""" "close" "exit"