- Does the interface actually have that item stored in it? If it's not stored locally in the interface then there is nothing to extract.
- Is the pipe configured to pull? The same configuration that would allow the pipe to pull items from a chest should let it pull from the interface.
Here's a couple of things to look over:
- Is the AE network powered?
- Are the items that you want to extract from the AE network actually in the network?
- Are the items that you want to extract stored in a fashion in which they can actually be extracted? (Direction setting)
- Can the items actually be transferred though a pipe? You should be able to figure that one out by the test earlier.
If this still doesn't resolve your problem come back armed with pictures. AE is hands down one of my favorite mods in modpacks.