Welcome to the forum.
What are the full specs. of those AV files? What make/model of camcorder, did they come from?
What was the Project Preset chosen at New Project?
Im using a Canon full HD powershot elph 300 hs camera. The project asked me to use setting that fit my camera and click ok. Im a novice when it comes to all of this. I just got into video editing for personal hobby, and pickup up premiere element because i heard it was the best on the market.
What are your system specs? I suspect that a full HD clip playback can have issues if the machine is underpowered. If it is only audio, please clear Media cache and then let the conforming happen again. Conforming ensures the audio is converted to a format that Premiere can play back. It stores the "conformed" file in the media cache.
For clearing the media cache, close down PrE, go to <user>\library\application support\adobe\common\ and delete everything there. And for letting conforming happen again, reimport the clip into premiere elements or simply reopen the project.
Try this and let us know
When you first import your video, before you do anything, do you have a red line over the video on the timeline?
If you do have a red line as described above, your project and your video do not match
Read Bill Hunt on a file type as WRAPPER http://forums.adobe.com/thread/440037
What is a CODEC... a Primer http://forums.adobe.com/thread/546811
What CODEC is INSIDE that file? http://forums.adobe.com/thread/440037
Report back with the codec details of your file, use the programs below... a screen shot works well to SHOW people what you are doing
For Mac http://mediainfo.massanti.com/
Once you know exactly what it is you are editing, report back with that information... and your project setting, and if there is a red line above the video in the timeline, which indicates a mismatch between video and project