error code 10 with sqlitedb map files in ext2 partition - p

[ext2sdcardpartition]

i have a bunch of sqlitedb map files created with mobac that, as the size of some of them exceeds 4GB, it is obliged to locate in a ext2 partition in order to bypass FAT file size limits

the second partition of my external sdcard, the ext2 partition, is mounted to /sd-ext/
i store the sqlitedb files in /sd-ext/osmand/tiles/ (as this files were used by osmand, but now i want to move to locus)
i have changed the permissions of each file to drwxrwxrwx (allow read write and execute permissions to owner group and others)
the owner and the group of the dirs are "root"
the owner and group of the files are "root" for some files or "sdcard_rw" for others

all that does not make a difference, when i run locus, after long time scaning files, i get an error screen with as many entries as sqlitedb files are in /sd-ext/osmand/tiles/
the error entries say:

File: /sd-ext/osmand/tiles/
nameoffile.sqlitedb

Error: error code 10: disk I/O error


or just

Error: Unknown problem



Osmand seem to read the files fine, why Locus cannot?

Any hint on this, greatly appreciated..

[Menion]

Hi,
  to be true, I have absolutely no idea why this happen. Android itself (in version 4.0+) is limited to 4GB size on FAT partition. On ext2 it should work correctly. Also as you wrote, it works in different app

as I see, there are two possibilities

• create for me a log. Check this method http://docs.locusmap.eu/doku.php/manual:how_to:creation_log
• share one of not-working map with me, so I can check it on my device

also please write me what Android version is on your device.