Weird problem
 

When posting a message if I use the preview feature, the message contents appear ok in the preview area, but don't show in the editor, so that when I then click on submit message I get the "message is too short error"

I also have the same problem when I edit a post.

I'd like some idea's on how to cure this.

I'm using 4.2.1

look like there is something wrong with your settings,

ok, just quick check, go to settings/Message Posting and Editing Options/Minimum Characters Per Post------------ check the value there

also go to settings/Message Posting and Editing Options/Maximum Characters Per Post------------ check the value there,too

if things are fine in both options, then you will have to run a diagnostic test...

What version of PHP is on the server?

I'm running it on Hawkhost using MySQL 5.5

Not MySQL, but PHP - what version of PHP are you running? 4.2.1 will have issues like the one you are describing if you are running PHP5.4 or greater.

Sorry

According to hawkhost they are running PHP 5.3 I have another site on Hawkhost and thats fine

And what version of PCRE? If it is 8.21, then you need to have your host either downgrade to 8.20 or upgrade it to fix the bug that is in that version of the PCRE software.