Bob,
It's a bit hard to debug a version that old. In some cases, if it's related to a bug that's already been fixed, the only option you have is to upgrade. But I'll tell you what...... I understand the pain you've been through with your daughter. I actually work at St. Jude Children's Research Hospital in Memphis, where we've been pushing survival rates for children like yours for over 50 years.
What I can do is *give* you the latest version (11). If that fixes the problem, we're golden! If not, we can begin to work through the possible issues. Later versions will actually give you more detailed information during the login process that we may be able to use to trace this down.
Download this and give it a try. It's actually still in BETA, so may give you some warnings about expiring, etc... Ignore those for now. Let me know your experience and we'll go from there.
www.celestialsoftware.net/telnet/AbsoluteTelnet11.05RC1.exe
Other improvements in this version:
Better support for windows 10
Additional host key and key exchange algorithms
64-bit version for 64-bit systems.
Brian