Is there Audio in your file? What is the format/CODEC?
There is Audio in my files, the files are produced by an Sony Legria HF S10. I can play the sound with vlc Media Player, but in Premiere Pro CS 5, they said in the file is no sound!
Other files, like .mp4 had a little speaker on the clip, but .mts files not!
I used the Adobe Premiere Pro CS 5 German Trial.
Read the limitation of the trial on the download page. It answers your question.