Follow the instructions on the link that Vinit sent - use the Install Executable to get integration with Visual Sudio and DO NOT install any runtime on your development computer. The runtimes are for use when deploying your application.
If you're going to compile your app as 32-bit, be sure to use a 32-bit app pool in IIS.
You have to target one of the full versions of the .NET framework - the Crystal SDK will not work with one of the "client" versions of the framework.
Your code probably includes some lines in PageLoad() that will keep the report in session. This part of the code needs to be moved to PageInit() instead.
There are a couple of additional things you may run into, but do a search here before posting if you need help - there are lots of questions about this transition that have been answered here.
-Dell