I encountered the same issue. Tell me, does the computer you're trying to log into run a higher desktop resolution than the one on the viewer side? I wasn't sure if that could be the cause, but that's a possibility that occurred to me in my case.
I just installed Radmin 3.0 beta on two WinXP Pro computers and could use the Radmin 3.0 viewer to connect with Telenet, File Transfer, Chat, etc. but could not get the full control nor screen view only working. After I keyed in the username and password at the connection prompt, a Radmin logo flashed for less than a second and disappeared, leaving just the Radmin viewer address list window on the screen. I checked that the Radmin mirror driver 3 was properly installed in device manager.
How we can help you ?
I already have a couple machines with win95, 98 and working radmin2.2 .
I can instal beta driver and test it.
I was try to install driver provided witch this release od Radmin 3.0b and It was instaled on properly (without any conflicts), but it does`t work . (I still have a black screen).
From my experience, if there is any type of security software that blocks ports, registry or file system events, RAdmin may not fully install. You can either make the exception while doing the first install, and then reinstall. Alternatively, disable the software before attempting to install RAdmin.
Disconnect after authentication:
Disable Remote Desktop/Remote assistance