Below is the answer I gave to a similar (probably your) question, but given the language of your question here, perhaps I am wrong. If you didn't request the vacation as I mentioned, then perhaps you had a public defender who pursued an appeal on your behalf - but then it would likely say not guilty, not vacated. I need details you haven't provided regarding how this case ended.
Vacated convictions such as this mean that the individual was in fact convicted of the crime at one point, but the individual completed all terms of his or her sentence and remained free of trouble for a certain amount of time, and then asked the court to essentially undo the conviction.
In this instance, it seems the crime was misdemeanor possession of 40 grams or less of marijuana. Since the offense was in March 2007, then only 4 years have passed. Three years must pass to vacate misdemeanors. Class C felonies require 5 years beyond the completion of the sentence and Class B felonies 10. That's why I know this was a misdemeanor offense.
An individual with a vacated conviction may legally state for ALL purposes that he or she was NEVER convicted of the offense, so they are not lying if they do not disclose such on employment applications, etc. The reason behind this is individuals make mistakes and should be allowed to go on with their lives after a period of time that they've shown they are not "career" criminals.
A "vacated" judgment is legally void. It is usually a result of a successful appeal, but a court can vacate its own judgment under certain circumstances. See CR 60, http://www.courts.wa.gov/court_rules/?fa=court_rules.display&group=sup&set=CR&ruleid=supcr60
[In accordance with the Avvo community guidelines, this communication does not constitute "legal advice", nor does it form an attorney-client relationship.]
If you didn't ask for the type of "vacation" I mentioned earlier, then you CANNOT state that you were never convicted of the offense. If you didn't complete your sentence and no appeal was filed, I am as baffled as you. Human error is rampant in the courts. It wouldn't at all surprise me if this is some strange typo.