Hello I have Platinum and the AIR instruments vsti doesn't work fine. The problem is when I play my keyboard the sound takes a few seconds (lag). This problem don't occur in Sonar X3 or Reaper. Any suggestions?

Try adjusting your audio buffer with its ASIO driver. 

I don't this it is a driver issue. The delay is several seconds between the note on and the synth responding. The problem only occurs with release J. Prior releases of SONAR and the X series do not have the problem.

As I said is only in Platinum, in Sonar X3 and Reaper, works fine.  I adjusted buffer, I reinstalled the Vsti, but it doesn't work fine. The plugins are Vacuum Pro, Loom and Velvet.

I'm seeing this in JP too.  If I start an empty project (no tracks) add Vacuum Pro and then using the mouse (so no MIDI latency) click on one of the piano keys on the soft synth, I can then count to 5 before I hear the beep.  It's not a driver/sound card/windows/ASIO issue.  Something changed in JP.
 
 (additional info)
If I then arm the audio track for record and play something (midi or live) the latency goes away and things again begin to play in sync.  Having the audio track armed for record seems to change the behavior.

Try toggling the PDC button to see if that helps.

This sounds like what I saw when I upgraded to Jamaica plain. I found that when I enabled  a patch point, I was getting a massive delay with Midi to AIR plugs (Velvet in my case) - in a number of tests, the delay was 13 seconds from playing a note to hearing the plug in play.
Reverted to Ipswitch & everything is fine again.
 
Chuck

PDC doesn't seem to make any difference.  The only thing that stops this massive latency is arming the audio track the synth is routed to.  Don't even have to start recording or playback, just the arming of the track is enough.  But having VacuumPro feed into an audio track that isn't armed for record results in a giant delay.  This was working fine on Ipswitch.  Other AIR synths have similar problems (Loom , Velvet, Transfuser 2, Structure ) but not Hybrid or Strike .  I believe AIR has free trial versions now available, so it shouldn't be hard for Cakewalk to try this themselves.  Not doing anything special.  Insert VacuumPro synth, press key on synth's virtual piano.
 

I don't think it's a Delay compensation issue - it seems to only be with air instruments ( in my limited tests)
 
CHuck
 

"Having the audio track armed for record the latency goes away" thanks msorrels. I hope that Cakewalk in the next update fix this bug.