I'm stuck on level 4 at the part when you climb up the wall, then I go inside the building but none of the switches work. I've roamed the entire map practically and I can't find a key for the locked door or anything. And I've tried jumping across to the building with the windows but I just stutter off retardidly and fall. Please help me!!

You need to go downstairs and turn on the power by moving the block in the "basement" water wheel section to engage the gears, then moving the gears on the floor above to engage those. Then the switches will work.

YAAAA!!! Thanks for the tip!