I am testing an upgrade to SSAS 2008 and verifying existing reports working properly. I am able to get some SSRS reports that are using SSAS as a datasource to run without any issues. They are simple and only have a single dataset. The reports that I am unable to get to work correctly against SSAS 2008 have multiple datasets and have a fitler setup with a data range setup as a parameter. As soon as I setup that filter as a parameter and deploy them the report returns a "The connection either timed out or was lost. Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. An existing connection was forcibly closed by the remote host" message.

The funny thing is that the report works fine when I run it locally in BIDS and it works fine once deployed if I point it to a SSAS 2005 server. Once I point it to the SSAS 2008 server it fails. I can get other reports to work fine, but not the ones with this type of a filter setup. I can see that the start and end date parameter MDX statements get run in the trace, but that is it. After those run then we receive the transport connection message.

Another funny thing is that in the production environment the reports are working fine, but that has SSRS 2005 and SSAS 2008. Does this make sense?
What could be causing this? I have tried setting the single transaction level on the datasource too, but that does not seem to make a difference.