"Client error: Sorry, there was a problem with content of the entry"
Quick heads-up: if you're trying to post an entry on Livejournal, but cannot do so, instead getting a message saying "Client error: Sorry, there was a problem with content of the entry", as follows:
Then chances are good that your post contains a link that matches an entry on LJ's blacklist (which is presumably used to combat spam), so check your post for any links to sites you don't usually link to, especially non-major ones, and try and see if removing them helps.
A request to get a more informative error message (at least) has been filed, too; here's hoping it'll go somewhere.