Several users are reporting this error:
This same error was fixed in a previous update with a workaround described here. However, this can be caused by user error (downloading the wrong updater or wrong language), but most likely it’s caused by modifying files as described here. This includes modifying Office files as well as your OS file like removing languages. running Monolingual or Safari fix. [Added Sept 2010: For the latest info on this . . .
Continue Reading: 12.1.1 updater woes- a version of the software required not found