I must have spent hours trying things and looking online for a solution, and I can't find anything that works. Aspen Relay Coordination Software more. Any chance someone can offer a suggestion?

MSXML 6.0 and 4.0 can be installed at the same time because 4.0 has some legacy features that 6.0 does not include. AoM/TT needs MSXML 4.0 so having MSXML 6.0 installed will not make a difference. What OS are you using? The link the in FAQ is not up to date - MSXML 4.0 SP3 can be downloaded for XP and Vista. It doesn't include Windows 7 on the list of OSs, presumably because Windows 7 already includes MSXML 4.0 SP3.

If downloading MSXML 4.0 SP3 (and restarting) doesn't fix the problem, try the steps in Method 3.