Yeah -Mop-, I am having the same problem. Even installed the Interactive training missions and did as instructed - still did not work.
When I select a target type (Target Flashes on ABBRIS), then a wingman, hit send. The 'Send/Mem' stays flashing, indicating a problem.
Search this forum and tried some of the suggestions - Still no joy.
I have tried this on my standalone BS2 install (1.1.1.1) - Works fine.