(My) Vegas hates WAV files

I did some spots last week for a client who had some finished audio mixes sent to me from a local audio post house. They were 48k WAV files, it showed they were 8MB, and when I brought them into VP10 it's like they were in a coma on the timeline. I put them through dbPowerAmp as WAVs again and that fixed it.

Yesterday, I got a final audio mix WAV file from a different audio post house, and the exact same thing, only this time I couldn't cure the problem with dbPowerAmp.

Is there anything that could be causing this?

--Kelly