v1.1.2 b339 H4PC - MIDI failure, MTC problems

I am having problems with MIDI (specifically MTC) on Hog4PC.

H4PC is installed a Win7 64bit system. H3PC was previously installed and running (without MIDI/MTC). UAC is turned off and the user account is a computer administrator.

The MIDI interface is the M-Audio MIDISPORT 2x2 Anniversary Edition. I am using the latest drivers: v6.1.3.

Initially H4PC saw the MIDISPORT without issues. I was able to select port A or port B in the MIDI tab.

I unplugged the MIDISPORT from the main H4PC to move it to another H4PC to do some testing. The main H4PC prompted a dialog that read "Node does not support this feature" or similar. Since this dialog appeared, the MIDISPORT is not recognized by H4PC on either the main or backup system. The MIDISPORT was purchased new two weeks ago. I pulled an identical MIDISPORT from a known working production system and it too is not recognized by either system. Both MIDISPORTS are also not recognized by H3PC (v3.2.6) running on the backup system.

I have uninstalled the drivers for the MIDISPORT, H3PC & H4PC from the main system. I rebooted then reinstalled the MIDISPORT drivers followed by H4PC. Same results.

I've attached a snapshot of the log in H4PC. The two MidiConfiguration debug entries are written every time I click the MIDI tab in the Control Panel. The two dropdowns in the MIDI tab are highlighted blue, with no text/entry and nothing is shown if click the dropdown arrow(s). A Hardware.Midi error entry is written every time a cue is fired. I'm not sure of the context for the Showitems.Timecode entry - this snapshot was taken after a few reboots thus it is not the original dialog (which I dismissed without grabbing a snapshot).

I've also attached a snapshot of one of the callstacks.

When MIDI/MTC was working, it was temperamental. H4PC would not sync timecode reliably and would sometimes fail to sync until 10 seconds or more of MIDI signal was received (both regenerate and jump are configured for 0 frames, aka off). Other times H4PC would fail to sync all together, despite the presence of a MIDI signal at the MIDISPORT as indicated by the LEDs on the face of the unit. Interestingly, using the new metrics dropdown info dialog on the TC toolbar, the framerate was shown as ~15fps despite receiving a MTC clock configured at 30fps. As a quick test, I selected Simulate and ran the clock. The metrics info dialog showed ~30fps. I have not yet tested the MTC signal with another receiver.

The first problem to solve is getting H4PC to (re)recognize the MIDISPORT. It seems unlikely this is a hardware (MIDISPORT) failure because the MIDISPORT has been swapped for known working unit with identical results; the H4PC system has been swapped for a known working unit with identical results; H4PC software has been swapped for H3PC with identical results. All testing (including H3PC) was done with the same show file.

Once the H4PC recognizes the MIDISPORT again, I would like to resolve the squirrelly MTC synchronization.