The error message says that the server was requested to deliver
If you see your access log and look up the same time stamp as given in the error log you'll probably find something like this:
ip-address - - [14/Mar/2018:09:57:32 +0100] "GET /some/path/relative/to/your/domain HTTP/1.0" 200 1324 "http://your-shop.com/skin/frontend/theme/theme/" "Mozilla/5.0 (W...
As a summary there are basically two reasons for this log entry:
- Some user tried (un-)intentionally to access
http://your-shop.com/skin/frontend/theme/theme/ from browser directly
img tag set (i.e.
<img src="" />).
Hence, first of all you need to find what area of your shop is causing the error log entry - because based on the information given in your question it is impossible to tell where to look (it could be a path to a file where the last part is meant to be fetched from the database, yet there is just no result on that SELECT available; it can be a general coding issue somewhere; it could be some bad CMS entry; ...). Probably hitting
F12 in your browser and navigating through the shop should help you to find the problem. It's quit likely that the messaged printed to your error log comes along with a 404 in the console log in your browser.
Last but not least: Even though it is stated as an "error" in the log it is basically the best thing that can happen to your system. Because another possible behavior is that instead of logging an error is that the server returns a directory index (a list of all files and folders within the requested directory) which in almost all cases is not desired. The behavior of the server in general is specified within your