You should try the following (if you haven't):
- Replace your HSUpdate and SoulMS with the ones from the main site again. Just to see if that does anything.
- Try downgrading your HackShield with one of the programs (which may be located on this forum, I don't recall).
- Go to your task manager and end the process of anything Maplestory related (even the Ahn HackShield ones) and try loading the client again.
- Reinstall your entire Maplestory v0.88 or just download the v0.88 Maplestory.RAR from the SoulMS site (I haven't had any problems with that folder).
- After any of these, give your computer a quick restart.
Hopefully, one of these are the solution. Good luck.