There are several things you should look out for. First, make sure INFO(0) for all level exit objects are correct (this is undocumented; do not attempt to search for it in your manual).
**
1 = proceed to level immediately and numerically following this one
2(+) = proceed to alternatively-linked level that is numerically X above this one
-1 = retreat to past levels; cannot proceed to new ones
**
Second, make sure you have provided links both to and from your node. Else, you will only be travelling on a "one-way street" between nodes, not being able to go the opposite direction.
Another possibility is that you did not link your nodes correctly. Make sure that you inserted the links to other nodes (found in the 4x2 field box in the "Edit Node" dialog) properly. If they are not entered correctly, it will not work at all.
YES
1| 0
2| 0