That's fine. You're running a Debug build, which is meant for catching errors. This, however, is just fine and you can ignore it.
Select fs2_open_3_6_12r_INF.exe (the Release build) instead of fs2_open_3_6_12d_INF.exe (the Debug build) and you'll be fine. Or play with an earlier version of FS Open, or with the MediaVPs. Basically any combination except the one you're actually using.
For the grognards: Our missions are set to use starfield.pof but don't actually include it in FSPort core, so it will default to the retail starfield background.