cannot create incremental backs

I am trying to enable incremental backups with ghost 15 and I see this message: "The recovery set point option is disabled because you have already assigned a selected drive to an existing recovery point set backup job. You can only have one recovery set point defined for each drive."

I am using windows 7 32 bit how do I resolve this? Please send me an e-mail with any responce to

 

 

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