When I try to send a text it won't let me I get this message: The appplication Messageing (process com.android.mms) has stopped unexpectedly.
Try powering the device off, then removing and replacing the battery, then powering the device back on.
Update the PRL on the device by dialing *228 send and option 2.
Make sure you are using the default messaging application.
Then try clearing unwanted messages on the device.