I cannot install/play the new snapshots from the launcher.

It all installs fine, then I get this message:

Logged in successfully
Getting syncinfo for selected version
Queueing library & version downloads
Couldn't save version info for PartialVersion

{id='13w16b', updateTime=Wed Apr 24 11:51:24 BST 2013, releaseTime=Tue Apr 23 23:51:22 BST 2013, type=SNAPSHOT}

java.io.FileNotFoundException: C:\Users\Dan\AppData\Roaming\.minecraft\versions\13w16b\13w16b.json (The system cannot find the path specified)
at java.io.FileOutputStream.open(Native Method)
at java.io.FileOutputStream.<init>(Unknown Source)
at java.io.FileOutputStream.<init>(Unknown Source)
at java.io.PrintWriter.<init>(Unknown Source)
at net.minecraft.launcher.updater.LocalVersionList.saveVersion(LocalVersionList.java:73)
at net.minecraft.launcher.GameLauncher.playGame(GameLauncher.java:94)
at net.minecraft.launcher.ui.sidebar.LoginForm$1.run(LoginForm.java:122)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

The same has happened for snapshot 13w16a in new folders also