Did you search in DUC for anything related to the error you got? There have been licensing issues that have hit folks recently that are discussed here. Did you upgrade ILM? Which addresses the most common recent issue (that is not just just with PT First, that this article sounds like...).
http://avid.force.com/pkb/articles/E...hing-Pro-Tools (that does not sound like what you are getting... but upgrading ILM is usual troubleshooting anyhow).
What *exactly* did the message say? It is trying to upgrade to what? What exact Pro Tools 12 product (standard? HD?) and version are you running.
If that is not it, open a support case so folks here can escalate for you. One guess for random stuff like this us somebody has provided your iLok account info when trying to activate/upgrade a product. Think carefully who has that info, if you may have exposed it when say selling licenses to others.
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