Couple of things, 
1. Poor quality laminated wood, ends of both tops (where you connect hook for hammock), were already separating (not glued well). 
2. Instructions baffling, slight nuances in installation requirements not depicted in single drawing (without any text).  For example the bottom supports have a slight cut on the end that tilts slightly on ground, the indented bolt receptacles must also face a specific way. 
3. Cheap pine wood, don't expect it to last in the weather over the years, so put two coats of polyurethane paint to protect and to fill in separating gaps in top pieces mentioned earlier.