FreeRTOS CDC.inf issue on Windows

Using a very slightly modified version of the FreeRTOSCDC.inf file, I’m having trouble working with a SAM7X running FreeRTOS from a Windows app – I can open, read from, write to, and even close the USB connection successfully, but the one case in which it seems like the driver is not quite working is when the device is unplugged – subsequent calls to ReadFile() do not fail as I would hope/expect, but rather return with 0 bytes read.  Not knowing when the device is going to be unplugged, I’d ideally like to close the connection once a read fails, but I’m not able to in this case.  When the device is then reconnected, my app is in the wrong state.  Has anybody else experienced anything like this?  Thanks for any tips.