The two 'missing marker' errors are of concern .. it may suggest a bad route installation? But, before you do a full cache verify:
Take gptech's advice and clear the cache on the Tools tab of the RW Launcher.
If that doesn't fix it, here's something else you can try:
1. Open the scenario in the Scenario Editor
2. Hit F2 and confirm the save
3. Hit the big arrow at the lower right of the RW window to go into play mode
No one seems to know why this works, but sometimes it sorts out problems with consists. If you still get the error, quit and restart RW and try opening the scenario as usual.
As a last ditch effort, you may have to do a full cache verify. This, of course, will overwrite any mods you've made to your Steam supplied routes, scenarios and stock, so it should be done only if absolutely necessary.
Good luck.