When I tried to access one of the Projects, it tried to navigate to the following URL when it threw an 'Unexpected error' :
Name=Request (GET:https://project.****.***.***:443/PWA/ProjectDrillDown.aspx?ProjUid=63d1093a-7be7-46d6-8a39-e2bc4f5ae476)
Whereas when I tried to access the same Project a couple of times, it shows the following in the logs for the same Project ID:
Name=Request (GET:https://project.****.***.***:443/eppm/Project%20Detail%20Pages/ProposalStageStatus.aspx?ProjUid=63d1093a-7be7-46d6-8a39-e2bc4f5ae476)
They appear to be associated with the following line in the logs:
05/30/2012 11:37:48.66 w3wp.exe (0x2844) 0x03A0 SharePoint Foundation Runtime tkau Unexpected System.Web.Services.Protocols.SoapException: ProjectServerError(s) LastError=WorkflowCannotAccessPDPLibrary Instructions: Pass this into PSClientError constructore to access all error information at Microsoft.Office.Project.Server.WebServiceProxy.PWA.WorkflowGetProjectDrilldownInformation(Guid projectUid, String userPropToClear, Boolean bCheckOutProject) at Microsoft.Office.Project.PWA.ApplicationPages.ProjectDrillDownPage.OnLoad(EventArgs e) at System.Web.UI.Control.LoadRecursive() at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) c390fb92-6753-4350-ac9a-cf720d04c0c5