Redmine

Did you make any change to lib/redcloth3.rb?

No, i didn't.
It seems to me, that the problem is in som special messages in mailbox.
May be, this is a problem with Microsoft Exchange mail server.
This problem happen already 3 times.

Run the rake task with the --trace argument to get the full trace of the exception.

And please check your production.log file content.

Do you have any plugins installed (see SubmittingBugs)?

I've already run rake task with --trace parameter, and attached file is the result.
It's very dificult to get information from production.log, because the error occured on the real productive base, and there are too many lines in log file.
Of course, there are some plugins installed. There is the list of plugins.

Redmine Better Gantt Chart plugin 0.6.3
Redmine release notes plugin 1.1.0
Redmine Ft Import plugin 0.0.1
Smart issues sort plugin 0.2.5
Redmine Theme Changer 0.0.5
Redmine Wktime plugin 0.0.1
Issues XLS export 0.1.3

Could you save one of these emails in raw format (.eml) and post it here please?

This issue does not solved. No ideas?