Unable To Change Timezone In Control Panel

Since we started daylight savings time I have tried several times to correct for this by changing the timezone in the General Settings section. Each time I hit “save changes” and then it returns to the original time zone without accepting my change. (I never had problems with this in the past, such as when we went off daylight savings time last fall).

If this is not a known bug I have one possible idea. A couple of months ago my blog was hit by a hacker. Tech support for the company hosting my blog changed the permissions to disable writing for some of the files and/or subdirectories to make future attacks more difficult. I wonder if it is possible that the time zone is not changing because I am no longer able to write to the file which stores this. If this is a plausible cause, could anyone tell me which file stores this information so I can check the permissions?