A defendant’s misunderstanding of a term in a negotiation plea agreement, based on the erroneous advice of his attorney, will not invalidate a plea, absent a showing of corroboration by a responsible state officer. Appellant pled no contest to kidnapping in exchange for an agreement that he would be evaluated pursuant to Penal Code section 1203.03 and would receive a probationary sentence if the report was favorable. Otherwise, he would be sentenced to state prison for the middle term. The subsequent diagnostic study included a recommendation for probation by two clinical psychologists, a recommendation for prison by two correctional counselors, and a letter from the warden recommending appellant be committed to state prison. After the evaluation, appellant moved to withdraw his plea in the event he was denied probation. He argued that the denial would be a violation of the plea bargain because defense counsel had informed him that the sentence would depend on the result of the psychological evaluation (which was favorable), not the recommendation by the warden. The court denied the motion to withdraw the plea. Affirmed. Defense counsel’s erroneous advice, alone, did not require the court to grant the motion to withdraw the plea. Withdrawal would be appropriate if a state officer had led appellant to believe that only the report by the prison psychologists would be relevant, but this did not occur. Further, appellant failed to establish the required prejudice as he did not show that, but for the erroneous advice, he would not have entered into what was a favorable plea bargain, even with the denial of probation. The court also found that there was no violation of the plea bargain. Using contract principles to interpret the plea negotiation, the court concluded that the agreement, by necessity, must incorporate the provision of section 1203.03 that clearly explains that it is the warden’s recommendation that is controlling.