Hi Pam -
The way you handle the spacebar makes the difference. If you are facing a crate and tap the space, releasing it, you will climb. If you press the space and don't release it, you will grab onto the crate. Keep holding the spacebar down while using the arrows to push/pull the crate into position.
Were you able to use this technique to climb over a wall in Episode Three? That's where you received an object to trade for the "Effahid Flute." If you skipped that part, you didn't get the flute, which you must have in order to survive Episode Six.
If you are using my walkthrough, be sure to get a new copy of it next week, for I am making some major changes to the ending, Episodes Ten and Eleven.
That will be ten Dramoi.