Patch 1.11.0 doesn't work

[SuperSirius]

Hey guys Every patch for 1.11.0 doesn't work it always says this
The patch "WoW.exe" could not be applied. (Invalid source file size: expected 4542514, actual 4775986.) If this problem persists, you may be able to solve it by uninstalling and then reinstalling the game. If you are unable to correct this problem, please contact Blizzard Technical Support. (BNUpdate::PTCApply)

Can you help me with this? Because I really want to play on my private server. I am also playing on a lan but my oldest bro says I can only do lan because cox will be cocks and cut our internet. If they didn't do that I would be glad to have you guys play on my server but yea can you help me with this?

[Marlo]

reinstall wow like it suggests...