If you are having errors when installing the MUI language packs on Win7\Server 2008 R2 - the logs are located in the users profile appdata path:
Here is a snip of a log for an example:\
15:30:50:034 : PERF: Create language from CAB (C:\tools\langpacks\zh-hk\lp.cab) - ENTER
15:30:53:495 : DEBUG: CreateFromIdentity("Microsoft-Windows-Client-LanguagePack-Package~31bf3856ad364e35~amd64~zh-HK~6.1.7600.16385")
15:30:55:014 : DEBUG: CreateFromIdentity("Client")
15:30:56:784 : DEBUG: Client is not a language type package, or does not match the type of your OS (e.g., server language packs mismatched with a client OS). Check to be sure that you are using language packs which match your machine.
15:30:56:871 : WARN: Unable to create langpack
15:30:56:897 : WARN: CbsClient::CreateLanguagePackFromCabImpl(C:\tools\langpacks\zh-hk\lp.cab) failed with hr = 0x80070032