A recurring Timer does not stop recurring if the Rule Actions fail; it will recur as scheduled until you disable or delete the Rule. In the case of Timer Rules, "Stop processing this rule" means "do not execute any further Actions with this Rule" (such as sending an e-mail), but it does NOT mean that the Timer will stop. For example, if you have defined the Rule to run every hour, an Action in the Rule could fail (such as downloading a file from a remote computer), but the Timer will run again the next hour, and the next hour, and so on, until you tell it to stop (by manually disabling it).