Have you tried it without the spaces?
open ftpusername:@taic#$@10.10.10.117 -rawsettings ProxyMethod=3 ProxyHost=10.10.10.118 ProxyPort=8099

Also can you connect from GUI?

I have a FTP server wherein the following operations needs to be performed:

FTP Server Details:
Ftp Server : 10.10.10.117
Ftp Username: ftpusername
Ftp Pwd : @taic#$

Local Proxy Details
Proxy Host: 10.10.10.117


Here is the command line:

winscp> open ftpusername:@taic#$@10.10.10.117 -rawsettings ProxyMethod=3 Proxy
Host= 10.10.10.118 ProxyPort= 8099

After running the script I get following in console:
Searching for host...
Network error: Cannot assign requested address


Is it possible to connect to ftp server via proxy details if yes kindly help in getting this resolved


Thanks & Regards