Can't transfer files via scp because it returns : "File transfer server could not be started or it exited unexpectedly"

I'm using :

OpenSSH_3.5p1 (package)
Solaris SPARC 8

and the SSH FIle Transfer Client for Windows 3.2.0 from SSH Security Comunications

and when I try to connect to the server as any user, even root, displays :

File transfer server could not be started or it exited unexpectedly. Exit value 0 was returned. Most likely the sftp-server is not in the path of the user on the server-side.

What can be happening ?

      Yuri Huitrón Alvarado
Administrador de Servicios de Internet
 Universidad Autónoma de Coahuila