We are trying to add an additional site to our MSM install, from four to five. Per the instructions we replaced the sites.php, sites_lang.php and Sites.php files with the new version. After doing so we get a 500 error when attempting to create or edit sites. The exact error in our browser is:
HTTP Error 500 (Internal Server Error): An unexpected condition was encountered while the server was attempting to fulfill the request.
I checked our Apache error log and no errors are reported. I double checked the file permissions and they are correct for our install (744, owned by the apache uid/pid). Rolling back to the previous files resolves the issue but it leaves us without the new site license.
Without an error in the apache logs I am not sure where to start troubleshooting. I did note that the build number for the MSM files has changed. The current version (that 500’s for us) is 20101215, and the working version is 20101018. I also note that the changelog does not show a 20101215 build, as seen here:
http://ellislab.com/expressionengine/user-guide/cp/sites/msm_changelog.html
Can you suggest a troubleshooting direction?
*Update* - I forgot to mention we are running EE 2.1.1, see the attached image file for a screenshot of Health Check for our site.