If you get the error message in MOSS farm server application event log:

Unable to load thesaurus file C:\Program Files\Microsoft Office Servers\12.0\Data\Office Server\Applications\xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx\Config\tsXXX.xml for lcid 8.Component: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx

Then it seems that you are missing the thesaurous file for the corresponding language pack. You can copy the tseng.xml to tsXXX.xml.