The error logs are found within the “logs” directory for your user. Quoting from the DreamHost wiki:
[quote]" Where are the log files for my domain?
They are available via ftp in your home directory, within the directory called “logs”. The full paths will be something like:
The italicized portions of the path above should be replaced with information relevant to you. Just look in the directory to see what ##### is.
Also note that your older logs are kept in that directory as well, and named things like access.log.1.gz. The number is how many days old they are and the .gz means they are compressed. You can uncompress them with something like WinZip or Stuffit Expander.
By default, we keep 3 days of logs, but you can change this to as many days as you’d like from the Status::Statistics tab (click the “days” link next to your domain). Any logs besides the last three days will count against your disk usage quota. "[/quote]
–DreamHost Tech Support