Improved error message

git-svn-id: http://h2database.googlecode.com/svn/trunk@5456 e6896862-9d19-0410-bfb3-e9fa5d50e656
Remove unused import

git-svn-id: http://h2database.googlecode.com/svn/trunk@5457 e6896862-9d19-0410-bfb3-e9fa5d50e656
MVStore: the file format was changed slightly.

git-svn-id: http://h2database.googlecode.com/svn/trunk@5458 e6896862-9d19-0410-bfb3-e9fa5d50e656
The Polish translation was completed and corrected by Wojtek Jurczyk. Thanks a lot!

git-svn-id: http://h2database.googlecode.com/svn/trunk@5459 e6896862-9d19-0410-bfb3-e9fa5d50e656
Shrink headers

git-svn-id: http://h2database.googlecode.com/svn/trunk@5460 e6896862-9d19-0410-bfb3-e9fa5d50e656