your database has become corrupted.
dont worry, its easy to fix:
on your h10, navigate to rockbox menu -> settings -> general -> database and choose initialize now.
or, via either a computer or rockbox's own file browser, delete all the database_n.tcd files (eg database_0.tcd, database_1.tcd etc), as well as the database_idx.tcd file, from the .rockbox directory. this will force rockbox to recreate your database and is sometimes necessary if the first method doesnt solve your problems.
for your second problem, rockbox at the moment doesnt scan for metadata changes in the media files. the only way to make the database 'see' the changes is to recreate it via one of the methods above. this is why i usually fix all my metadata (sometimes over a period of days) and then recreate my db
