Not going to claim to have all the answers...but a few things I've picked up from differing threads on here seem to have helped out when taking my Boreham Wood side from BSS into (currently) League 1...and sitting in 7th first year there coming into Christmas 2017 :)
Firstly - when you play...
I've fended off L1 teams trying to poach my N/C left back while in the Blue Square Prem by offering him a new contract after they have approached him...
Usually if a player will negotiate a new deal with you, even if it's another N/C deal, they will sign that over moving to another club...this...
Isn't that somewhat realistic though?
They don't know what date the Spanish Cup final will be played in real life still, or even where it will be played (mainly as Madrid don't want to see Barcelona winning it at the Bernabeu!)
The 'Rolling Contracts' are the "Non Contract" option - you don't pay players a weekly wage you just pay them appearence money...only problem with this is they can leave whenever they want for no fee (so not great for promising young players!)
I ran into a similar issue when I started a game at Boreham Wood and could only get players to sign Non-Contract or Youth terms....
What I figured eventually was the board blocks me giving contracts to any players that aren't given "Key Player" or "Youngster" squad status - until you change the...
Might be worth putting Steam into "Offline" and the trying again?
I had an issue one point with Steam saying FM2010 was unavailable when online and it was due to a broken update that Steam was trying to download for Left4Dead2 :@ and as Steam couldn't stop the update when online it made other...
Apparently the "lic_dan_swe_fra.lnc" file renames some competitions/tournaments in the Danish, Swedish & French leagues that couldn't be used due to licencing also...