AE refused to start so I reinstalled it from CS4 Production Premium discs. The installation was fine althought I got an error message while loading (about an audio file, if I remember) but AE started however.
I decided to update it to 9.0.3 assuming it would resolved this error, but instead it displayed this error:
xxx sweetpea failure [I have a french version: "After Effects impossible de continuer: échec sweetpea"]
(48 § 58)
And then a message that AE can't continue...
Intel i7 930 @ 2.80Ghz
Windows 7 64
Motherboard MSI X58 Pro-E (intel X58 chipset)
AMD Radeon HD 5750
Audio Realtek High Definition (from motherboard)
Dual Display 1440x900
Thanks for helping me!
Update1: I tried reinstalling AE once again, and had exactly the same result.
Update2: Tried the workaround found in aeerrors.myleniumstuff.de (renaming/removing the openGL plugin), AE still doesn't start, same error.
You may have a problem with your onboard audio chipset. As explained in various audio-related erros on my site, turn off things like virtual surround or other DSP enhancements nad also make sure to map your outputs correctly to the primary stereo channels. Likewise, configure your devices to a sample rate that AE can handle, i.e. in most cases simple 48 kHz. And of course check your device manager whether the audio hardware is flagged in any way and may need a new driver...