WinVNC 4 strange message and command line question

[Jackson, Simon (Computer People)]

Hi,
I am looking to remotely control around 100 Xp workstations from management
PC's. I need to be able to do this from the command line. Can I do this  -
Is there an option to pass a username and password to the remote machine for
authentication. Is there anything I can do to prevent this being a security
hole. Is VNC the right tool to do this sort of operation with?

Also, I have pulled down the trial version and have got the following
message when attempting to connect to a server:

The VRMC connection could not be established because Protocol version 3.6 or
later is required.

I cannot find any help on this by searching the website and I didn't get any
detailed documentation with the trial software.

All help and comments appreciated,
Regards,
Simon.