Where has it gone today? In Mediaplayer it sounds nice.
Audioformat of source is 44 100 Hz --16 bit --stereo,
audioformat of project is 44 100 Hz -- 32 bit floating point -- stereo.
What model of camcorder is this video coming from, and did you use Premiere Elements to get this video from the camcorder to yout computer?
Also, which version of the program are you using and what operating system are you running?
Also, when you Imported the media files into PrE, did you allow the program to fully Conform the Audio? With 44.1KHz 16-bit, that should not take long, but the time needed will depend on the Audio format/CODEC. With PCM/WAV @ 44.1KHz 16-bit, it will go so quickly, that you might not even see it. For more info on Conforming and Indexing of files, see this article: http://forums.adobe.com/message/3892177#3892177
The CFA and PEK files are stored on your computer in the Media Cache folder within the destination, that you set, for the Scratch Disks. Where are your Project's Scratch Disks located?
Since WMP (and also the Source Monitor in PrE), directly access the media file on the HDD, where PrE's Timeline and Program Monitor access the CFA (Conformed Audio) and PEK (Waveform Display) files for editing, there is a problem with the Conforming process, or linking to the CFA and PEK files.
If you cannot hear the Audio from the Timeline, the link to the CFA file is bad, and if there is no Waveform Display, then the PEK file cannot be accessed.
I would Delete the files from the Timeline and the Project, then go to the Media Cache, and Delete the matching CFA and PEK files, then Import the media again, allowing just a bit of time for the Conforming process to complete.
The Media Cache folder will be where you directed it in Edit>Preferences, and the default is Same as Project, but can be changed by the user.