The logfile is stored in the “User Directory”.
The location of the user directory is shown under “Help -> About”.
Inside that directory the logfile itself can be found in the sub-directory var\log
and is named messages.log
You can display the log file directly inside the IDE using “View -> IDE Log”. The first view lines of the logfile also include the information about the user directory.
That is helpful if you just want to copy & paste a part of the logfile (e.g. the exception of the error you are reporting).