Instead of positioning the mouse pointer in the vertical center of the Title (or Link) box, as is normal, you have to move the pointer upwards very carefully. With the pointer positioned just below the top edge of the box, the pointer will turn into the standard insert icon, and you can click in the box, and start typing.
This has been observed in both Firefox and Internet Explorer. You won't solve (workaround) this by changing to another browser, or by clearing cache and cookies.
It's the weekend, and this is a fairly simple and non-intrusive workaround (unlike the one for the bX-mzm63b error). I'm betting that this won't be fixed for a few days, so we better get used to it.
>> (Update 7/9 11:15): Blogger Employee tells us
It seems that this issue is a result of a fix we pushed out on Friday. We're working on fixing things up as soon as we can.
>> (Update 7/9 13:00): Blogger Status advises us
Some users are reporting that they are unable to enter titles for their posts. We are currently investigating this problem and working on a fix.
>> (Update 7/10 17:30): Blogger Employee tells us
We're almost finished w/ the fix for this issue, which means it should be out shortly (I give it one day max).
>> (Update 7/11 13:00): Looks like this has finally been fixed.
>> Forum thread links: bX-*00056
>> Copy this tag: bX-*00056