Media Encoder stopped working

Hello,

I'm having a problem with Adobe Media Encoder. When I try to open it, I get a pop up message saying:

Thank yo for using Adobe Media Encoder CS4. The Adobe product that installed Media Encoder has not activated. Please launch and activate that Adobe product before continuing to use Media Encoder.

Then of course the program won't open.

I just use it a couple of hours ago and it was working fine. I converted a quicktime file to flv. When I watched the flv file to see if it worked. Then I got an update from Adobe Air. I installed it and I could still use it. When I was done I closed both the programs. The Media Player is still working, but the Encoder isn't.

I've tried to restart the Macbook. I updated Media Encore. I've opened every Adobe program there is, to see if it activated something, but no luck.
Can someone please help me? What do I have to do to get it working again?

Thanks,
Irene Meijer