There are two possibilities, both related to the conversion of the original MXF file.
1. Premiere Elements 4 cannot interpret the file correctly.
2. The project cannot conform that audio to the audio properties of the project preset.
(What is the project preset? Do see a conforming audio process going on when you import the file into the project? If so, do you wait for completion before doing anything else in the project?)
First we need to confirm that Sample Rate of 1.0000 Hz. Please put your sample through the free video audio properties readout program and tell us the video audio properties that are shown for that sample. MediaInfo download | SourceForge.net
Be careful in your choices downloading and installing MediaInfo since it known to travel with unwanted baggage.
What is the video compression used in these files that have the .mov file extension. AVCHD (MPEG4 AVC/H.264)? Premiere Elements did not support AVCHD until Premiere Elements 7.
Do you have the latest version of QuickTime installed on your computer?
Lots to explore. Let us start by confirming that Sample Rate of 1.0000 Hz.
We will be watching for the details in your reply.
The answer is probably
1. Premiere Elements 4 cannot interpret the file correctly
In the meanwhile I learned that my filmmaker friend inadvertently gave me files with 5.1 surround sound. Evidently Windows Media Player can recognize and play this audio, but PE 4 cannot.
He reconverted a test file, which I have downloaded and tested in the PE project. The audio track appears and plays.
Thanks for the help.
Thanks for the update and glad that the new video sending from your source worked for you. But, although you report "Problem Solved", I suspect that do not have the right reason.
Did you ever confirm the Sample Rate of the original sending a 1.0000 Hz?
When you imported the file from the original sending into your Premiere Elements 4 project, what was the situation
1. You heard the sound, but did not see its representation on Audio 1.
2. You did not see the audio portion of the file on Audio 1 and you did not hear sound from the file?
There is more to this than the following pointing to audio called 5.1 channel....as you wrote
Evidently Windows Media Player can recognize and play this audio, but PE 4 cannot.
Given Premiere Elements 4 is an older version which does not have project presets described with 5.1 channel sound. For that matter, there is no category for AVCHD video since that was not supported until version 7. However, I can import a 1440 x 1080 HD anamorphic 16:9 video which comes with 5.1 channel sound into Premiere Elements 4 without issue. This file has WMV3 compression, WMA audio 5.1 channels, file extension .wmv. But here is the problem at first glance. You can hear the audio, but you do not see the audio representation on Audio 1. That is because of the way that 4, and even 7, handled 5.1 channel sound. If you do not use a project preset described for 5.1 channel, the video will go to Video 1, but the audio will go to an upper audio track (in my case Audio 6).
I am glad that you received a sample with properties that worked for you, but to avoid this type of problem moving forward it might be a good idea to go deeper into the properties of your video, especially in relation to the support matters raised by using an earlier version 4.
Please let us know if you need any clarification on the above.
Best wishes with your Premiere Elements projects.