Welcome to the forums!
Regarding your testing environment, are you surrounded by any tall trees or buildings? Please place the device where it has access to an open sky.
Have you tested the BU-353-S4 with GPSInfo? If not, please download the program from here: http://www.usglobalsat.com/store/downloads/GPSInfo.zip
Make sure to select the proper com port and baud rate. Click on the Start GPS button. Wait for a few minutes and see if could a get a GPS fix.
If not, press the Cold Start button and observe.
Also, can you please register your product and generate a support ticket? Please check your email for further instructions.