latency problem in only one project ??

I can not figure this one out: I suddenly have a huge latency problem (almost half a second or so) in one of my projects. All the other ones I recently woked on are fine. I tried to change the Buffer, reset the Audio Interface
in Device setup ( Rosetta 800 ) … in VST Connections I swiched on and off the Rosetta, nothing helps.

I use Cubase 5.5.1 on a 2x2.8 Ghz Quad Core Intel Mac , OSX 10.5.8 … 16 GB Ram, any Ideas someone??

Where exactly is the latency, input monitoring, record, playback, certain tracks, all tracks? Precise description would help. Is delay comp enabled in that project?

… it happens on midi tracks, when I play the sampler the sound comes almost a second later. When I play guitar rig, same. Oh, did not check delay comp, will do when back in studio next week. I exported all audio and midi and then imported them into a new project, now all works fine. But still I really would like the reason why it happened.
Today while work on another project it happened again, but after restarting Cubase5 and the rosetta800 it was fine
all day … ???