The order absolutely matters, as some mods require others to be loaded first. Follow this order, and you shouldn't have any problems:
Top to bottom:
1. Avanced Combat Environment ( ACE )
2. Community Base Addons ( CBA )
3. 506th
4. RHS: Armed Forces of the Russian Federation
5. RHS: United States Forces
6. RHS: GREF
7. CUP Terrains
8. KaluKhan
9. AlRayak
10. Task Force Arrowhead Radio ( TFAR )
11. STHUD ( Optional )
This is what I load in with, and I do not have any issues.