I wanted to mention a problem I've been having for months in FL Studio 10 -- but have resolved.
When you open a project containing a Virus TI, sometimes (not always) the Load process hangs, and the Info boxes go white, so you can't tell where it's hanging. Both of the Load boxes at the top/bottom are blanked out, and it looks like the Virus has already loaded, because it was the first one to get displayed.
When I disconnected the Virus TI and re-opened the project, it opened with no problems.
So when using FL 10, I advise to turn off the Virus TI while opening the project, and only turn it on once the project has completely loaded. Then the plug-in will auto-detect the connection and initialize itself.