Database doesn't work after working with 3.2 and opening in 3.1.1

Hi
I played a little bit with 3.2m57 with an hsql database file i 
created since 3.0. With 3.2 i changed table definition (defaults), 
lack up the report and insert more data.
Al worked well. But after i close the database and want to open the 
same file in 3.1.1 i got an connection error. The statusbar shows 
JDBC, not hsql. And after opening the same file again in 3.2m57 i 
got the same error.
What can i do to get the right connection back? I don't need the 
file back, have backups, but it would be nice if this file can work 
again.

Thanks
Ulf