It's the mod, not background programs, although having only Warband open does help... There are classes that some of us call, "Locked." It's a community term for mod items that cause cheating problems. Often times, these "locked" objects, classes, or whatever are only accessible by admins, or are only available on certain maps. here is a list of the locked classes, thanks to some testing (Note... This is only for British):
Specials ---> Otto, he was a reporter for the British Army Column... He is locked.
Cavalry Officers ---> All cavalry officers except Frontier Light Horse officer and Boer Commando Officer.
Infantry Officers ---> 60th Rifles Officer and the 32nd Infantry Officer.
Sapper ---> Certain maps, like Rorke's Drift, don't allow the use of the sapper, and if he does work, you can't build anything and may only spawn with a spade at times.
I hope this helps you to understand what works and doesn't. Do your best to avoid the above classes when playing, or you'll get kicked for "cheating."