Threaded loading has been removed a long time ago, since it was giving more issues then we won with it. And it was never made public@HomeY: Does it make sense to test our feature called "Threaded plugin loading"?
Or are you talking about something else?
The LoadSkin error(s) is extra logging (only visible with debug logging enabled) that was added to give pointers to the team when something is running on the wrong thread. It's been in there since 1.7 (JIRA).
If i'm right, those LoadSkin errors shouldn't even be noticable during use of MediaPortal, but i'm no dev.
@Sebastiii you have any additional info about this?