Quick way to find which log file is logging errors
On development systems it is common practice to have different log file to log PHP error logs for different tools and different versions of the same tool. Generally it is a good idea to use meaningful names to make it easy to distinguish between the log files. If you have doubts, you can either look inside the code to see which error log file is being called or do the following:
$ cd ~ $ ls -al /var/log/httpd before.diff
Run the tool such that it would write something to the log file. Then
$ ls -al /var/log/httpd after.diff $ diff before.diff after.diff
The diff file would show the file(s) which have changed. Read these files to see whether they are indeed the correct files.