.MTS Files missing Audio after import into Premiere Pro

I have the Creative Cloud Suite and Imported several .MTS Files. Next I added and edited the files in a sequence and the audio was working fine. A few days later I opened the project and the audio was gone? I have no idea what could have happened. I removed the files from the project and re-imported with no success. Has anyone else had this issue? Very frustrating because I have used the . mts files in the past on other projects with no problems.