Don't worry.
Files on OpenKM can be stored on several ways, dbms ( postgre, mysql, oracle ) or file system.
By default The OpenKM configuration save files on file system under Jboss/repository, but are saved on a special structure - refer to jackrabbit if you want more information about it.
One think that always we've got present since starting OpenKM is that end user is owner of files, and if want to move to other system this must be done easilly, we think it's some to evaluate comparting to other dms.
You must not try to recover - find - files from this structure (it's special blobs structure not tipical to facilite fast access and other improvements). On OpenKM there's a way to export all data structure to normal server file system. Connect as system user, go to admin menu options, an select export option.
Take a look at this
threath about exporting option.