UPX compression
By the way, have you considered using UPX compression on your executable? When I compressed your EXE file it went from 2.4 M down to 700 K, and it still appeared to run.
It is compressed with UPX. WinSCP 2.2 (#122) application has 666 KB :-)
Uncompressed is EXE file is only in installation package. Some people reported that some anti-virus applications consider WinSCP packed with UPX as a virus.