Obviously everything isn't fine else you wouldn't be posting
The error you are reporting tells me that you either didn't visit the ACP Medal Configuration page or you did and it reported SQL errors. If you didn't, then please do so. If you did, then some of the SQL is there and some of it isn't. Go into your config table and remove the row for medals_mod_version. Then, revisit the ACP configuration page.
Pay attention to the output. I would recommend copying it for reference later.
FYI people: My next release will have a note explaining the SQL as done by the auto install.