Surge protectors can have "filters" in them as part of the protection. The filters will filter out RF frequencies. The "pass the net over the powerlines" type adapters, use RF and the RF gets filtered out by the surge protector.
Many of the power nic adapters have a second frequency they can use, which may or may not be filtered by whatever surge protector your using.
Here we had the same problem even if surge protection power strips were on the same "curcuit" back to the main box of the house. Eventually we gave up on using this type of trasmission, because of all the UPS (Uninteruptable Power Source) Power strips, and other filtering that was done even in some electronic devices.