Im using variables also yes.

1. What is the correct way of updating EA's in Metatrader. Should I download .mq4 or .ex4 file? If i make changes in EA then how should I apply it to Metatrader? Should I take it off from a chart, close Metatraderm and then add the new EA to the folder and then run Metatrader again or I can simply add it to the folder and refresh the EA?
2. Also I was wondering may copying blocks of EA cause any errors? Im running 6 EA's on 6 different charts and it doesnt want to work really well. At some point I got some of them working. Then I copied some working features to other EA and it got broken again.