dgen 1.18 and 1.23 are already in OE, I included them myself. Your setup must be incorrect in some way, because I have tested both and they both load and run (but 1.23 segfaults loading roms (on both PC and Zaurus), and 1.18 seems to sit there doing nothing on loading a rom (on Zaurus, works fine on PC)).
I recommend you do something along the lines of:
ipkg-link umount <path>
ipkg remove libstdc++6 --force-depends
ipkg update
ipkg install -d <dest> libstdc++6 --force-overwrite
ipkg-link mount <path>
Replacing dest and path with the correct destination/path, assuming you didn't install to root.
Also, a tip to people wanting to add things to OE: Check that they aren't already there!