Tvheadend

Hi,
I have been investigating my 404 errors: sometimes, when I schedule several recordings at the same time, some of them are unable to start. This is normal (at the same time, my tuners are recording some other programs). But when the failed programs are ended, these recordings are listed as "Completed OK" in the HTTP interface and in XBMC, which results in 404 errors when trying to play them.

• a syslog file showing such recordings. Here is one of them:
  

  Aug  7 20:44:30 pchc tvheadend[9567]: dvr: "La malédiction du plastique" on "ARTE HD" recorder starting
  Aug  7 20:44:30 pchc tvheadend[9567]: dvr: Recording unable to start: "La malédiction du plastique": Adapter in use by other subscrip
  tion
  Aug  7 20:44:30 pchc tvheadend[9567]: subscription: No transponder available for subscription "DVR: La malédiction du plastique" to channel "ARTE HD" 
  Aug  7 20:44:58 pchc tvheadend[9567]: dvr: Recording unable to start: "La malédiction du plastique": No input detected
  [...]
  Aug  7 21:18:57 pchc tvheadend[9567]: dvr: Recording unable to start: "La malédiction du plastique": No input detected
  [...]
  Aug  7 22:14:20 pchc tvheadend[9567]: dvr: Recording unable to start: "La malédiction du plastique": No input detected
  Aug  7 22:20:00 pchc tvheadend[9567]: subscription: "DVR: La malédiction du plastique" unsubscribing from "ARTE HD" 
  Aug  7 22:20:00 pchc tvheadend[9567]: dvr: "La malédiction du plastique" on "ARTE HD": End of program: OK
  

  
  

  Aug  7 22:36:25 pchc tvheadend[9567]: HTTP: 127.0.0.1: /dvrfile/12308 -- 404
  

• a screenshot of the TvHeadend Server web interface showing this recording as "Completed OK"

Quite weirdly, the first error is "Adapter in use by other subscription" and the next errors are "No input detected".