Crystal Deployment Issue

Question

I am having a problem deploying Crystal Reports to a test server. The site is an ASP.NET 4.0 site developed with Crystal version 13.0.1.220 engine for .NET. The site is deployed on Windows Server 2008 R2 64 bit using IIS 7 and Plesk.
I've had multiple errors only with the report which I've managed to resolve with the exception of this one. Below is the error I get whenever I try to load the report. I also loaded Visual Studio onto the server and tested the actual solution there. That worked fine. I assume this is permissins based so ended up adding permissions to C:\Windows\Temp and to the site directory. Still no luck.
Any help would be greatly appreciated. Without further adieu, the error:
Invalid file name.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.Runtime.InteropServices.COMException: Invalid file name.
Source Error:
An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. 
Stack Trace:
[COMException (0x800001fb): Invalid file name.]
   CrystalDecisions.ReportAppServer.ClientDoc.ReportClientDocumentClass.Open(Object& DocumentPath, Int32 Options) +0
   CrystalDecisions.ReportAppServer.ReportClientDocumentWrapper.Open(Object& DocumentPath, Int32 Options) +95
   CrystalDecisions.ReportAppServer.ReportClientDocumentWrapper.EnsureDocumentIsOpened() +270
[CrystalReportsException: Load report failed.]
   CrystalDecisions.ReportAppServer.ReportClientDocumentWrapper.EnsureDocumentIsOpened() +333
   CrystalDecisions.CrystalReports.Engine.ReportDocument.Load(String filename, OpenReportMethod openMethod, Int16 parentJob) +877
   CrystalDecisions.CrystalReports.Engine.ReportDocument.Load(String filename, OpenReportMethod openMethod) +85
   ReferralTracker.ReportWriter.CrossSaleReport() in C:\Customer\ReferralTracker\Reporting\ReportWriter.aspx.vb:89
   ReferralTracker.ReportWriter.Page_Load(Object sender, EventArgs e) in C:\Customer\ReferralTracker\Reporting\ReportWriter.aspx.vb:17
   System.Web.UI.Control.OnLoad(EventArgs e) +91
   System.Web.UI.Control.LoadRecursive() +74
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2207
Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.1

Answer 1

After adding permissions everywhere for everything... I ended up adding NETWORK SERVICE to the C drive with Read and that worked.