Are you trying to add photos if so make sure they are less than 3 Meg as you cannot upload anything bigger I had the same problem and this seemed to be the problem?

I find this happens if pictures are near the 5mb limit. 4.7 and upwards seems to cause this for me Kath.

I've also had that error when trying to upload a photo that was too big. Do you get the error at any other time at all or just when trying to post?

Its been happening when trying to post .

Try clearing cookies Kath - I was getting the same message trying to log in a few weeks ago, as were quite a few others. it seemed to work for most of us

Mine was like that last night as well Scotkat took three attempts to get my blog on, hope its ok for you now...