The title screen says 3.5, which seems to be the latest version (the character may've been created before that). Khand (105 str), Dunlendings (210 str), and Umbar (780 str) are all creating advance camps in Rhovanion, near Fangorn and the (destroyed) Isengard Hunting Camp.
It's not hard to destroy them, as they often are filled with raw recruits so I can do it with no help, but no ally lords want to seige the Dunlending's main camp (Dunlander Camp) to defeat them (Isengard is gone already, since all I had to do was kill the last stand army) and I can't suggest it as a target, only advance camps. I tried attacking the Dunlander Camp myself but I can't (I assume for balance reasons).
They first set up the advance camps when they had over 1000 strength. The way I got their strength below 1000 is by destroying them over and over. They just never stopped creating them after that threshold, so I didn't know it was a bug at first.
Rhun, Gundabad, and Dol Goldur were destoyed earlier, so Erebor, Dale, Beornings, and Mirkwood also have advance camps near Mirkwood and the Beorning's Woodsman's Village (but they are all above 1000 strength, so I guess there are no problems there). Gondor and Rohan are defeated too, hence the many advance camps. Lothlorien is also destroyed.
I'm also getting messages every now and then, especially after defeating an enemy lord, saying "Script Warning: Division by zero; Line no: 295
At script: decide_faction_ai.
At script: decide_faction_ai.
At script: decide_faction_ai." repeated a few times. Sometimes the "Line no" is different, I'll update with the other numbers if/when I get it again.
Hope this helps, I tried to be as detailed as possible.