UIRT transmit failed with error code 0

I've been stepping through diagnosis with the developers of Intelliremote who leverage the usbuirt.dll.
We enabled the debug logging in their app and found that there is apparently a blowup in the usbuirt.dll.
I transmit a signal in to the usbuirt which triggers an autoit script that generates a different ir transmit. (Your standard purpose for a usbuirt.)
Here's where things go off the rails...
In the log:
2/2/2009 1:21:23 PM [DEBUG] Line 5: UirtTransmit( 500, 5, "0000 007C 0000 0011 000A 0048 000A 0048 000A 0048 000A 001F 000A 001F 000A 001F 000A 0048 000A 001F 000A 0048 000A 001F 000A 001F 000A 001F 000A 001F 000A 001F 000A 0048 000A 001F 000A 0377")
2/2/2009 1:21:23 PM [ERROR] Problem with command UIRTTRANSMIT: (UIRT Error) UIRT transmit failed with error code 0
At this point the app hangs and we get a 'send the error to Microsoft' dialog.
I've seen several posts in the forum that suggest that there are problems with the 1.4 dll. I have tested this on 4 different installations of XP (SP1 or SP3) and the behavior across all of them has been identical.
Help!
We enabled the debug logging in their app and found that there is apparently a blowup in the usbuirt.dll.
I transmit a signal in to the usbuirt which triggers an autoit script that generates a different ir transmit. (Your standard purpose for a usbuirt.)
Here's where things go off the rails...
In the log:
2/2/2009 1:21:23 PM [DEBUG] Line 5: UirtTransmit( 500, 5, "0000 007C 0000 0011 000A 0048 000A 0048 000A 0048 000A 001F 000A 001F 000A 001F 000A 0048 000A 001F 000A 0048 000A 001F 000A 001F 000A 001F 000A 001F 000A 001F 000A 0048 000A 001F 000A 0377")
2/2/2009 1:21:23 PM [ERROR] Problem with command UIRTTRANSMIT: (UIRT Error) UIRT transmit failed with error code 0
At this point the app hangs and we get a 'send the error to Microsoft' dialog.
I've seen several posts in the forum that suggest that there are problems with the 1.4 dll. I have tested this on 4 different installations of XP (SP1 or SP3) and the behavior across all of them has been identical.
Help!