I am having the exact same problem!!
I have a file which is over six hours long, but when I got to the 3:32:09 mark, if I let off of the pedal, the next time I depress to play, although the slider marker appears to be at the same spot (about midway), the audio has returned to the beginning. No matter where in the audio, from that point forward, I try to reset the marker --- even near the end -- I am back to the beginning of the recording. All pedal commands are wonky (play is fast forward, rewind is fast forward, fast forward is fast rewind -- even though I test them again) Now, if close the file, reopen it, slide to my position, depress the pedal and never let off of the pedal, the recording continues to play just fine, but only to the point until I let off again.
This is driving me c-r-a-z-y. It is a .wma file. Fortunately, I have the .wav file of the same job, but I preferred using the .wma file, since it was 2-channel, and the deponent is a mealy-mouthed mumbler. 