Unable to place ladder block onto a normal block(mud,cobblestone,etc..) which is next to a door (on any plane) See Screenshots.

Solution:
1) Remove door Block
2) Remove block previously next to door block
3) Replace block just removed, now able to place ladder block!
4) Door can be replaced once ladder blocks are in place.

Screenshots show:

Stage One = Unable to place ladder block
Stage Two = Unable to place ladder block even though door has been removed
Stage Three = Now both door and blocks next to door(cobblestone) have been removed and replaced ladder can be placed on block.

Thanks.