Redid the patch with ARM7 just now and just to be sure, reinstalled YSmenu 7.06 too, and nope, still "error -4".
Have you tried patching a clean rom with the patch file provided by Retrogamefan instead ( it's in his YSMENU topic, page 1), and then relaunch using the v.7.0.6 update. Make sure your existing savefile name matches the rom, else it won't get detected. I've tested it and confirm working fine.
Just for the record, Original R4 DS (Non-SDHC) run the game fine using v.7.0.6. Sleep mode works too using the latest YSMENU. I can't confirm about those previous bug reports, haven't reached far due to non-gaming activities. But assuming the bugs are related to the translation file, then likely it's not resolved.