Can you tell us the version of Captivate product you are working on?
Also it would be great if you can send us a sample audio file. We will check it here and tell you how you can solve your problem.
Kindly email me one of the same files at firstname.lastname@example.org
I've seen this issue before and it is most likely due to the bit rate at which the WAV file was created.
You may need to open the WAV file in an audio editing application and change the bitrate to something that Captivate will accept. (If you don't have Audition or Soundbooth then download Audacity, it's freeware.)
I think you'll find WAV files for Captivate have to be 16bit PCM format and not 24 or 32 bit.
In addition to what Rod suggested, the encoding of the WAV file may be incorrect. For example, I have a WAV that I always use in Captivate classes to demonstrate this exact issue. The file has a WAV extension and plays fine in Windows Media Player, but it has ben internally encoded to MP3 format.
Normally all I have to do is open it up using Windows Sound Recorder, click Save As, make no changes and save it out as a WAV and sound recorder does its thing and the WAV is then usable in Captivate.
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...and one more suggestion, moreso related to Rod's...
We've had import issues in the past with .wav files as well. In this case, they were audio files create on a Mac. I'm not sure of the exact cause, it might have been because they were recorded at a 32kHz...?
All our .wav imports are 16bit, mono, 22 or 44 kHz and generally work as expected.
Regardless, whatever the cause, I echo other comments about simply opening the audio file in some capable audio editor (I too recommend Audacity) and doing a 'save as' (or in the case of Audacity, an 'export'). That's always solves the incompatible file issue for us.