How do I find/look at JBidwatcher's error logs?

For JBidwatcher to log anything about its operation, you have to have Logging enabled in the General tab of JBidwatcher's Configuration Manager. If it's logging, then you can find the error logs by looking in JBidwatcher's home directory for files named error.##.log (where ## is a number).

On Windows it's usually:
C:\Documents and Settings\{username}\.jbidwatcher

On the Mac it's at:
/Users/{username}/Library/Preferences/JBidwatcher

On Linux, it's just:
~/.jbidwatcher

You can view it with more, or any text editor in Linux. On Windows, Notepad or Write will do the job. On Mac OS X, if you double-click the files it will open Console.app, which will work very well.