Unable to launch singleplayer scenarios

[anno1505 1]

Hello when I'm downloading scenarios from the steamworkshop or from armaholic I get these messages

http://i.imgur.com/aW9dst1.jpg (125 kB)

And then this

http://i.imgur.com/077fgSw.jpg (118 kB)

I tried reinstalling ArmA3 but the same error came up, not sure what to do.. been browsing the web but no result.

Any ideas?

[5133p39 16]

http://forums.bistudio.com/showthread.php?162959-Cannot-play-steam-mission