Today I visited a customer site where the customer had setup a central store, meaning all group policy defintion files and language files are placed in the SYSVOL share for better management of group policies. One benefit of that central store is that all administrators managing and editing group policies are using the same templates.
The problem in this case was that whenever they started editing a group policy they got tens and tens of warning about various admx files along with for example resource errors. I looked into PolicyDefinitions folder in the SYSVOL share and immediately noticed that there was admx and adml files missing and that there were mismatch between the version of the admx and adml files.
I took a Windows 7 with SP1 client and added/replaced all admx files from there. After that I took the en-us folder and replaced what was in the SYSVOL folder with that one, followed by doing the same for the sv-se, i.e. the Swedish language files. While at it I installed IE9 and put in the inetres.admx and respective adml files for each language to have the capabilities of editing Internet Explorer 9 policies as that is to be included in the Windows 7 image. Voila!
So the bottom line is; keep the central store consistent and make sure that when you create the store that you populate it with admx and adml files from the latest client OS with service pack when managing Windows 7, and that you do make sure that you have the same version of all admx and adml files or else you will get errors due to mismatching files.