Downloaded the install package for CMS 6 R2 to get an old EPiServer site work in editmode. Installed it but saw that instead of the supposed version 6.1.379.0 it installed a 6.2.267.1 version. The site went corrupt since it also changed some of the dlls inte project but could reset those from the svn. but why the change of version number? Are there any updates I should do based on this and since this is a Commerce site will those updates work with the Commerce version?
It states on the download page that the version is 6.1.379.0: http://world.episerver.com/Download/Items/EPiServer-CMS/EPiServer-CMS-6-R2/
An EPiServer installation contains of a number of CMS Core files (containing the API), and a number of Framework files (containing framework and services). The Core and Shared files will be versioned differently.
For CMS 6 R2, Core files will be versioned 6.1.379.x, and Framework files will be versioned 6.2.267.1.
Here's an overview of all the Core and Framework file versions: http://epiwiki.se/configuration/episerver-version-nummber-vs-release-number/episerver-cms-6-r2 and the version history http://world.episerver.com/Download/Items/EPiServer-CMS/EPiServer-CMS-6-R2/
(Beware that there have been several patches to CMS 6 R2 over the years, which means that if you download the CMS 6 R2 package today the file version number will likely differ from what your old site runs. The latest patch version is 6.1.379.1000.)
I suspect some of the files your project references are the wrong version. Clear out your /bin and check that all your references point to the correct version files. Also check your web.config if the <dependentAssembly> version mappings are correct.