v2.5.17 update not working - database error - Joomla! Forum - community, help and support

i trying update few sites v3.3.3 2.5.17 update option not showing in menu. have tried use extension manager reinstall 2.5.17 update error:

jinstaller: :install: error sql db function failed error number 1061
duplicate key name 'idx_image' sql=alter table `jml_languages` add unique `idx_image` (`image`);
sql =
alter table `#__languages` add unique `idx_image` (`image`);
files update: sql error file db function failed error number 1061
duplicate key name 'idx_image' sql=alter table `jml_languages` add unique `idx_image` (`image`);
sql =
alter table `#__languages` add unique `idx_image` (`image`);

i have used akeeba admin tools option "repair , optimize tables" still doesn't work.

any ideas? don't want go mucking around in phpmyadmin , hacking tables...

many thanks,

jerrym

[post edit: have forum post assistant can't find "show fpa" option, how use fpa here? ]

have tried updating latest version of 2.5 first, , performing upgrade 3.3?

when upgrades 3.3, set new joomla 3.3 site, , import of information in. allows me work through of extensions , template issues inevitably come sort of major upgrade. might better path take in case.