Why does this happen every time I make homemade bread?!!?

The only bread recipe I have had success with is banana nut bread. I do have success making pizza dough. That's it. Any other recipe like sourdough, french bread, basic white bread, etc. fails miserably. I do not even make it past kneading the dough. I prepare the dough from scratch and when it comes time to knead it the dough won't form. Instead it always ends up crumbly to where it won't form into dough or a ball in order to set aside to let rise. Am I missing something? Or could it be my atmosphere in my home? I live in the mountains and I was wondering if too much humidity is the cause? I do have high humidity in my home and elevation is 1,200ft. Elevation shouldn't be an issue because usually those measurements are required at 3,000 ft above. I never had this problem when I lived elsewhere. Seems to be only here for some reason. Anyone know what could be causing my problem? Suggestions/advice appreciated. No I will not do packaged ready made dough =)