This is due to the fact that you are having a sold or kicked player in your next lineup. It is solved in the source, so if you are running from source you can upgrade. If not, you can do the following (assuming Win):

rename c:\Documents and settings\user\Mattricks\ to Mattricks2

Start Mattricks again, everything will reload.

Delete the matchorder-files (match_order-m*.xml).

Run mattricks from the command line with the command import, like (standing in the directory where all your XML:s are saved):

mattricks.exe import *.xml

If it is working properly delete Mattricks2, if not move it back and wait for the next release.

/Oscar