Settings > Miscellaneous in 3.5.1? ("Unable to create directory" …)

Greetings —

I am getting the dreaded error:

“state_street2.jpg” has failed to upload due to an error
Unable to create directory wp-content/blogs.dir/1/files/2013/04. Is its parent directory writable by the server?

I have read several forums and tried several possible fixes. No go. One of the common strategies seems to be go to Settings > Miscellaneous and remove the beginning ‘/’ from /wp-content/ leaving it wp-content/.

I’m willing to try anything at this point.

But when I go to Settings > … there is no Miscellaneous in 3.5.1.

I’d be really grateful for any tips or advice.

Thanks very much, in advance —

Best,
Michael