This error can occur when the Erwin 3.5.2 model, from which the ERX file was created, was corrupted in a particular way. Erwin Support has a fix, Build 528 or higher, that will prevent this corruption in future models. Since the fix needs to be in place when the model is created, it should be applied to all Erwin clients.
Since Build 528 does not correct existing corruption, the following method should be used on existing models that have this corruption. After Build 528 has been applied, open the corrupted model(s) with Erwin 3.5.2 and do an Edit > Select All and Copy. Then create a new blank Erwin model. Paste the clipboard into the new model.
From this new model, generate an ERX file, again according to the instructions in the Repository Erwin Interface User Guide or SupportConnect.ca.com's Document ID FAQ262530. Then run the Erwin scan on the new ERX file.