Have you installed an older release of NX afterwards?
Have you turned off your anti virus software during installation?
This error indicates that there is the wrong version of the DLL loaded, I think there is an article in the GTAC solution center to help resolve this.
Development: C (ITK), .NET, Tcl/Tk Testing: NX12.0 | AWC 3.4 Preparing: NX12.0
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