Sounds to me as if the OP is using the device as a "class compliant" (CC) one. Which is not surprising with teh cheap units as the rely on this USB1.1 compliance within the OS (MAC Windows, iOS) to provide the basic in/out drivers.

Most of the simple CC devices are known to exhibit behaviour such as this especially when asked to cope with advanced midi operations that most DAW software and programs like BIAB need. And they are especially known to crash when using it for more than one app at a time.

Example if using a CC device the Windows OS is also using it as the default MIDI, use it as well for BIAB...this is where you need the advanced operation capability provided by the "recognised" manufacturers. Most Edirol (Roland) devices allow you to select between advanced mode and simple mode using a switch on the device, but you are still required to install the Edirol drivers under advanced mode for multi-tasking operations, including multiple ports.

I suggest the OP gets himself something like the Edirol UM1-SX or similar. Simple but extremely solid, and pretty cheap too!

Dennis