With the recent publication this week of this Project Portfolio Server 2007 document: Project Portfolio Server 2007 Guide: Configuration Recommendations and I since I have seen a lot of questions on the subject lately, please find a recap of the software requirements for Portfolio Server 2007:
Project Portfolio Server 2007 requires a 32-bit machine. There is no 64-bit version and the installer will not run on a 64-bit operating system. In addition, the administrator needs to install the reporting tier on a 32-bit reporting server.
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