Crystal Reports Crystal Reports XI On Windows Server 2003

Message

   I've installed Crystal Reports XI, Developer Edition on a Windows Server 2003, Service Pack 1.

I'm accessing Crystal Reports using ASP Classic and it all seems to work fine.

On a client's server, however, the code doesn't work. I get:

Microsoft VBScript runtime error '800a01ad' 
ActiveX component can't create object 
/Customer/reports/AlwaysRequiredSteps.asp, line 15 

Line 15 being: 

Set session("oApp") = Server.CreateObject("CrystalRuntime.Application.11")

The client's server is also Windows Server 2003 but has Service Pack 2 on it and it seems to be the 64 bit version which we don't have.

Anyone know if this could be the problem? Or any other ideas what might be going wrong? Thanks.