Looking at the date in that version number, I'd also highly recommend you get the latest version so you're properly up-to-date. There have been a *lot* of new features added since then. As well, it seems quite likely that you don't have the original firmware files on your device anymore. If you want to get the original firmware working, you'll need to grab the MTP Updater Utility from
here and reinstall the OF. This will end up formatting the device as part of the reinstall, and since it won't find the OF version you'll need to tell it where you bought your H10 from before the updater will continue. Once that's done, you'll need to re-download your bootloader from
here (this is linked directly to the file) and the most recent firmware for the H10 20GB from
here (again linked to the file directly). Rename the H10_20GC.mi4 file on the device in the System folder (you'll need to have "Show hidden files and folders" enabled in Windows Explorer) to OF.mi4, then copy the H10_20GC.mi4 you downloaded from the link I put in earlier to the System folder on the device. After that's done, extract the contents of the rockbox.zip to the root of the device (as in, not in a folder on the device, the .zip will create the folders automatically). After *that* is done, copy your music onto your device in any folder you like.
Note: *ALL* of this must be done in UMS mode, which is entered by holding the "O" button down with the device connected to the computer while turning it on. You'll need to disconnect the device after reinstalling the original firmware for the installation to complete, then you'll need to turn it off, press the reset button with a paperclip or something similar, then reconnect, hold "O" again, and power it on while holding "O" to get back into UMS mode.
I hope this is helps...