Unable to reply to a message

Every since the board was updated I've been unable to reply to messages. I found that I can start a new thread but not reply. Every time I try to reply my reply is deleted and I get the following message.

The message you have entered is too short. Please lengthen your message to at least 1 characters.

When I contacted Chris he said some others had experience this same problem but didn't know why. It's probably something that I'm doing wrong but I don't know what. I was just wondering if anyone that has had this problem has found a solution or can tell me what I'm doing wrong.

Thanks
Dave