Since EZ Tolerance Analysis is a license extension, you need to have it added to your session at startup.
In the .psf file you are using to start Creo there is a line that looks like:
ENV= CREOMPA_FEATURE_NAME=PROE_EssentialsIIM......
That line must end with a numeric code in parentheses to specify that EZ Tolerance is to be loaded. For example, the .psf file I use to start up when I want manufacturing has (10114) at the end of the line.
If this all sounds like nonsense to you, well, fair enough. Licensing is pretty strange. You might have to get your IT folk involved or talk to the people who provided your licenses and have them guide you on setting things up to allow EZ Tolerance to be available.
I'm not sure what the directory structure is for Creo 8.0, but for Creo 4.0 I can run the "reconfigure" program in "C:\Program Files\PTC\Creo 4.0\M120\Parametric\bin" to modify/add these types of things.
