A quick post for Windows users of the LaTeX plugin. I just updated Sumatra PDF from version 1.4 to version 1.6. Unfortunately, forward search stopped working 😦 I checked, and this (mis)behavior has been present since version 1.5, which I had skipped. (Inverse search works fine, BTW).
I reported the issue to the developers; in the meantime, please use version 1.4, which works fine. You can get it from here (equivalently, navigate to the Download section of the SumatraPDF, and look for the link at the bottom of the page).
Edited (6/9/2011 at 11:45p): ends up there was a bug in my DDE code that Sumatra 1.4 forgave, but later versions did not. If you pull the most recent version from GitHub, you’ll be fine with Sumatra 1.6 as well. I am not sure I fully understand why the fix was needed, but I checked my code against this and figured out what I was doing wrong.