I joined with the name Long John Silver got a admin ban immediately i don't see the reason

You were banned because you have disabled grass, plants or rock textures and models.

See - http://www.zerosurvival.net/rules/

The ban will not be lifted.

i disabled nothing i recieve everytime a error when starting arma oa about failed to load file "c:/program files (x86) / steam / steamapps / common / arma 2 operation arrowhead / pmc / addons / air_pmc.pbo" - decryption of headers failed
the game runs fine i see grasss or plants or textures and models never got any problems getting a ban for any models missing i don't know how i get this error got this a long time never bothered me but i will look how i could fix this

This check has been a part of the same anti hack code most servers run for a quite some time now and it originally comes from 1.8 dayzmod. I've yet to see a false positive for it and can't see how one would be possible given the way the check works. I suggest you verify your steam files if this is the case but until I hear otherwise from the developer of the code the ban will remain.

i verifed my files still have te error, i can still join any other server without a problem, tryed to look how i could fix this. going to reinstall arma 2 and arma 2 oa and dayz

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