doesn't sound right, but I have never fun a report in 11 that was created in a prior version.  Are there any command objects?

what my thought was, is that for some reason, while it is running the command object, it is taking a long to retrieve the results, and the command object is probably linked to a parameter selection somehow.  Then it is taking just as long to process the request.

I don't use command often, but what I would try is to 1) run the select from the command by itself in the DB and see how long it takes...if it is taking close to 10 minutes...even 8 minutes to run, well, there you have it.  I suspect that it won't.  Next I would copy the command out of the existing command object, delete it, create a new command object and paste the code in.  Save it and see the report performs any better.