I had problems loading shapefiles directly to my Trimble. The solution was to create a new folder on my desktop and use it as a junction between ArcMap and the Trimble. As an example, I would prepare my data in ArcMap, use the ArcPad data manager to "Get Data for ArcPad." But instead of sending the data directly to the Trimble, I would send it to the junction folder on the desktop. From there, I would click and drag the data to the Trimble.
There is no explanation from ArcGIS as to why I can't send the data directly to the Trimble, but this method works for my situation.
I hope this helps. Good Luck!