Error: Unable to retrieve Object. Object reference not set to an instance of an object

After installing Crystal Developer to a working Crystal Server installation the ability to import RPT (report) files to the Crystal Server was no longer available even though the default path had been changed for the Crystal Developer installation to prevent issues with the existing Crystal installation.

Applying Crystal Developer Service Pack (SP) 2 resolved the issue. The current download page is accessed from http://support.businessobjects.com/downloads/service_packs/crystal_reports_server.asp

This can also be an issue related to a lack of licensing inside Crystal. Be sure the Crystal license is installed and recognized the Crystal installation.