Cannot open database files saved with latest version of Keepass v1.20.
Which format you use when you save the file?
KDBX not supported, only the KDB.
The original message says version from KeePass v1.20 and this will not save in kdbx. only kdb is possible.
I haven't checked, will give update.
If possible, make new problem sample file with password `123`. Attach it here.
FIle added as requested. This is using version 1.2 not 2.x and not using KBDX
Check 1.4.0 RC1, should work