Are you having MMS problems with your Sprint HTC EVO Shift 4G? Apparently, many users reported running into problems when trying to send a multimedia message from their HTC EVO Shift 4G. It appears that the carrier, together with the manufacturer, are planning on an update to fix that soon.
It should be rolling-out over-the-air on August 8 and will bring your version number to 2.76.651.5. After applying, the MMS problem should be solved. Unfortunately no other information is available and, besides fixing the “intermittent failure to send MMS”, there’s really not much more to it. Are you still using MMS or are you just sending emails/tweets with pictures attached?