Sorry, of course you did. I would not do a full new install just yet.
It's possible that that file is just corrupted, especially if you used FTP to transfer all the files. I've also seen cases where a particular language file is corrupted to begin with. It's easy for that to happen because of the way Git handles text files.
You might try redownloading MODX, unzipping it, and just replacing that file.
BTW, do you have the compress_js and compress_css system settings turned off? If not, that's definitely worth a try. You can do it in the modx_system_settings table in PhpMyAdmin (where you could also change the Manager language if you want to try that as well).
------------------------------------------------------------------------------------------
PLEASE, PLEASE specify the version of MODX you are using.
MODX info for everyone:
http://bobsguides.com/modx.html