root acces deneid

Hello, i have a virtual machine created with vmware workstation (linux ubuntu 10.04 i try with others distr. like kubuntu 8.04 , debian 6) and i have installed openssh-server and when i try to connect with my phisical pc windows 7 with winscp protocol i use is SFTP i cant connect with root with others users yes but with root no ,and o have in the file /etc/ssh/sshd_config the line "PermitRootLogin yes" i i cant ...
What is hapening :S ?

Thx

Have you restarted the SSH server after setting the PermitRootLogin?