BTW...it is the exact same thing with a plug in called Catanya. Catanya is basically a midi arp. You set it up with enable midi out and it drives any vsti.
You can run a single instance of Catanya but as soon as you set up a second instance it plays for about 5 seconds and then hangs so bad that you have to reboot the PC. Whatever audio is stuck plays until the windows shutting down screen appears.
This has been repeatable and reported since Sonar 8.5 I think. I have upgraded PCs, Operating systems, Catanya came out in a 64 bit version, and I am now on X3b and the same thing. It crashes so hard there is no report to send. If there was I would spam CW with the reports.
I have set up at least 5 instances of this plug in reaper and it never crashes. I can use reaper as rewire device running Catanya in Sonar and it will not crash.
Don't hold your breath about any action on this one. I can only assume that they know what the issue is, but it is a fairly extensive and expensive repair to the midi engine and as it affects a small group it is very low down on the plan of record.
Other than this annoying and on going saga, X3 rocks. This is the only way I have been able to crash things so far.