It means you ignored the "Read mod description!" marker, and selected multiple skins that overlap/conflict
So go to the skins on the list, and uncheck some of them.
Would give you a better list, but you forgot to attach log files
You selected multiple skins for the same tank, please read the notice on the things you selected.
It clearly says "[read mod description!]"
For example skins you picked:
Begleitpanzer 57 Remodel (Milkym4n)
T-64A (Milkym4n) [read mod description!]
T-90A (Milkym4n) [read mod description!]
T-54AM Remodel (Milkym4n) [read mod description!]
You would need to logout, and then login with the other account, activate/and what not, and then login to the game afterwards.
I don't think you can easily switch any other way... but maybe someone else knows better
There are mods that change your mission based on what you picked for what tank - so that could also be a factor.
Otherwise a mod wouldn't prevent you from completing an activated mission.
That's not a warning. That's just an attempt to get your attention. Just ignore it. There's no harm in it.
"- updated all mods made by ekspoint (with tag: [ekspoint]) - such mods may display a link to this modder website on the game interface. If you don't like it, don't use that mods."
You won't find the same old functionality, that let you target someone through a building - that was made illegal more than a year ago.
There is still similar functionality in the Autoaim Indication mod. (And it's in the modpack)
http://forum.worldoftanks.eu/index.php?/topic/441413-092101-autoaim-indicationaddins-no-proximity-snapping-for-autoaim-but/#topmost