Hi! I'll try to help you out.
1) You need to delete/erase the path located next to the "Log File" button in the Analyse/Clean-up window. That path may be associated to a folder that doesn't exist or was moved to another location. Problem solved!
If you want to generate a new log for the current operation, you need to click on the Log File button, and then on "browse". You'll have to choose the wanted location for the log. And that's it!
2) You need to fix the missing/damaged tag by replacing it by an undamaged one: delete or cut the missing/damaged tag and copy the undamaged one at the same place. Click on "Fix document" in Trados Menu or Ctrl+Alt+U. Then click on Save. Now the problem should be solved.
Good luck!