You need to talk to your IT department and get them to give you permission to Run Captivate As Administrator. Otherwise you WILL experience all manner of issues, especially if you ever need to capture screens for a software simulation... Iv'e worked in plenty of large organisations and it is usually possible to get this permission if your manager is willing to support your request. The alternative can be a life of misery with Captivate.
However, your issue with the audio files could be something else entirely.
Check to see if the audio clips have little or no silence before and after the voiceover section. If so, then I recommend you open each clip in Captivate's Slide Audio dialog and copy some audio from between sentences or pauses somewhere in the clip and then paste this silence at the beginning and end of the clip. You should aim to have around a half second of silence at each end of the voiceover.
You cannot just use the function in Captivate that adds silence as this is very pure silence that has absolutely NO audio data. Unfortunately, when Captivate sees no audio data at the beginning and/or end of a clip it simply truncates this silence. So your silence needs to be what I call "dirty silence" not 'pure silence". As long as there is SOME audio in the silence Captivate will leave it alone.
Also, make sure your clips are NOT hard up against the start or end of the slide. Back them off at least one tenth of a second.
See if that helps the issue.