I received this error too and resolved the issue by removing the install.php file from the www folder. I am using symbolic links though. I am not sure if this is an issue if your website isn't using symbolic links. (1/11)
I moved a website on Dreamhost from one user account to another and encountered this error. I did a dev/rebuild and it corrected the error. (1/12)
We are experiencing this issue as well. We are on dreamhost. I note they use symlinks for the log files. I turned off XCache and thought that sovled it, however I note the problem has come back. Sometimes there, sometimes not. Very frustrating.
Don't know what SS tries to log. Will rip it out of the code to solve it, if only there was documentation about logging!