Based on log entry it seems that DiscoveryProfile cannot be deserialized and processed on APE.
Most probable cause is that something is missing (package, assembly) on APE.
I have some quick tips that may help:
1) do you have exactly same version of all products installed on MP and all APEs including hotfixes and buddy drops?
2) do you create this profiles using Orion SDK? Do you use same script for profiles on MP and APE? Which poller do you use/call for creation of this profile? in case you use SDK, could you please paste relevant parts of the script?
3) do you see same behavior when you create discovery profile using SDK and Web UI?