We started including a version check on the game in the NAM 31.2 release, mainly as we had issues with people trying to blame the NAM Team for things that were actually issues with the original game, and solved by EP1 Update 1 (the 1.1.638 patch). There's 5 different SKUs for EP1 Update 1, each for different regions. As some disc copies purchased in more recent years may have been originally intended for a region other than where the user may have purchased it, sometimes, this will pose a complication. In that case, it may make sense to try other SKUs.
Additionally, if you're using a No CD hack, the NAM installer will not consider that to be a valid installation, mainly as there's no way of telling if the other game files are actually updated properly.
-Alex