We ran into an issue today at a customer site as described below. Come to find out that the Display Specifier lost much of it's objects and running forestprep again will resolve this. The issue is listed below as well as the KB875300 that describes the fix.
Yesterday, during an install of the first E2K3 server in an existing E5.5 site, we ran into an issue. Another E55 site showed no display name in E55. Although this display name had been updated almost 2 years earlier. We manually pulled E55 replication around the Org and the issue appeared to resolve itself. The install yesterday completed without errors. No RUS was needed and none were created.Today, we worked on another install of the first E2K3 server in another E55 site, which completed without error as well. However, this time when he went to create a new Recipient Update Service (RUS), the error "Invalid Argument - ID 80070057 was displayed. We have since tried to create a RUS on two other E2K3 servers using different permissions, always with the same error.
According to KB875300, re-running ForestPrep will replace the missing Display Identifiers.