I just updated LanguageTool from 2.5 to 2.6.
I use it in LibreOffice 4.2.5.2 under Windows 7 for German Spell Checking.
When I opened an existing ODT document I got many pop-up windows with NullPointerExceptions in AgreementRule.
Since I don’t know how to get the Java outputs as text, I made a screen shot:
Thanks for your bug report. This has already been fixed a few days ago. You can get a fixed version from the daily snapshots at Index of /snapshots/