You need to provide system info, exact project info, what version of AE and all that. As a start, clear out the media cache and move your referenced audio files to a place outside the original folder, so they appear offline/ missing when opening the project... You can always relink them later. And naturally, check your system's audio configuration, your CoDecs and so on...
The PC is core2duo E6400/2.13GHz, RAM=3GB/667MHz with NO problem
I have After Effects CS4 is working very well,
I Have installed most of audio codecs
I can play ALL audio files, any format, except the "aep" files that I have dowloaded from internet as a part of music audio album.
These "aep" files may be constructed with another program , nor After Effects I don't know,
maybe constructed with After Effects and crashed,..
thanks for the answer