How Report Errors
An error is when the game notifies the user that something bad happened, they are typically both logged and displayed as messages in the game window:
The game will continue after most errors, but they may trigger more errors. Errors are often caught by the developers but sometimes they sneak into the Alpha releases. To report the exact messages, open interestinglog.html in your web browser and copy the contents into your bug report. The location of the logs varies by OS, see GameDataPaths.
A screenshot of the message is less desirable as compression and scaling artifacts obscure the text, and you may not see all the errors. It's very useful if you can remember the steps to reproduce the error.
http://trac.wildfiregames.com/wiki/ReportingErrors
you must try to be familiar with the trac. our wiki have some info about this kind of cases.