Error 121

After changing the language for the game I restarted it hoping that the options would take effect. But it actually gave me this message instead:

This application has encountered a critical error:

ERROR #121 (0x85100079) Version Mismatch
Program: C:\Users\tanguy\Downloads\Wow.exe

Unable to open DBFilesClient\Startup_Strings.dbc


WoWBuild: 12340
Settings:
SET locale "frFR"
SET realmList "logon.warmane.com"
SET hwDetect "0"
SET gxResolution "1600x900"
SET gxRefresh "60"
SET gxMultisampleQuality "0.000000"
SET gxFixLag "0"
SET videoOptionsVersion "3"
SET movie "0"
SET Gamma "1.000000"
SET lastCharacterIndex "1"
SET readTOS "1"
SET readEULA "1"
SET showToolsUI "1"
SET accounttype "LK"
SET Sound_OutputDriverName "System Default"
SET Sound_MusicVolume "0.40000000596046"
SET Sound_AmbienceVolume "0.60000002384186"
SET farclip "727"
SET specular "1"
SET groundEffectDensity "24"
SET projectedTextures "1"
SET realmName "Icecrown"
SET gameTip "7"
SET mouseSpeed "1"
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