The PS3USB library, as supplied, expects to find a device with a genuine Sony VID (Vendor ID) of 0x054C, and fails if it doesn't see one. You could try modifying the following lines in PS3USB.h...
//PID and VID of the different devices
#define PS3_VID 0x054C // Sony Corporation
#define PS3_PID 0x0268 // PS3 Controller DualShock 3
Replace the VID and PID values with those for your device.