Apple Logic Pro /LogicExpress Discussion

I'm having a problem working with imported .wav files (in L7).  These files play normally in 
other audio apps such as Quicktime, but when imported to a Logic audio track, the tempo 
of the audio playback doubles (or faster, perhaps), so that recorded audio sounds like a 
tape playing in fast forward or rewind speeds.  Adjusting the tempo of the sequencer has 
no effect on this.

I can't seem to find a way to fix this in Logic.  There is the workaround of converting .wavs 
outside of Logic and importing as aiffs or mp3's. That seems to work, but it's more 
arduous.  Can anyone shed any light on why this may be, and is there any way in Logic to 
adjust the 'tempo' of audio sample playback?

Michael