You or the superuser must be the owner, and it must not be writable by anyone but its owner

Seems odd to me that such a very nixy message should appear on a Windows system.
If you have Cygwin or MSYS2, you might like to see what they think the perldb.ini permissions are, and even try using the Cygwin/MSYS2 chmod() function to set the permissions to 0444 or 0644.
Dunno ... maybe that's just a silly idea that has no chance of working at all.

Cheers,
Rob