Try pulling your battery out and leaving it out for 30-60 seconds then returning it and turning the phone on, by performing a soft reset it can resolve a lot of common issues, since it's only happening on some of the messages, also you could try using a separate application for SMS/MMS messages like handcent possibly and you can always call Sprint tech support.
Thanks Shane, the battery pull did'nt work, so I called technical support and they updated my profile. I did not know tech support was open late at night on weekends. My phone seems to be working now, you were most helpful.
Sprint S.M.A.R.T Agents Sprint S.M.A.R.T Agent are here to help Monday through Sunday 6:00 AM CT - 6:00 PM CT. If you need to speak to an agent outside of these hours, please visit Sprint Chat