I can't import database from 4.0B3 to 6.41.2

[simbro]

I’m trying to import the backup made on V4.0B3 into a CHR V6.41.2 but the import fail with this mesage: “enabling back after import: cannot read database”

How I can fix this issue and use my backup into the new dude revision?

any idea?

Thanks
Fabian