Report Viewer Web part in SQL Server 2005 Reporting Services: "Object reference not set to an instance of an object"

There is a known issue with the Report Viewer web part using parameterized reports. The issue is described here: http://support.microsoft.com/default.aspx/kb/942530.

However, we ran into some cases where the cumulative patches did not resolve the issue. Here are the results from one of our project teams:

After a grueling 3.5 hour call with Microsoft support, we finally fixed the problem. The gory details are as follows.

First, the hot fix mentioned in the KB article was never included in Cumulative Patch 4 or 5. Cumulative Patch 6 was released today. However, the support group is still researching whether the hot fix was included in it or not. They will get back to me. To install the hot fix I had to uninstall Cumulative Patch 5 and then 4 from the Reporting Services box. Then looking at the hot fix, I realized that it was simply a newer version of “SQL Server Reporting Services Add-In for SharePoint Technologies”. So that perhaps explains why it wasn’t included in the Cumulative Patches 4 and 5. However, the support person told me NOT to install Cumulative Patch 4 or 5 over this hot fix as they contain versions of DLLs that may overwrite this patch. Again, they will get back to me whether this is resolved in Cumulative Patch 6 or not.

Secondly, this hot fix is required to be installed on all the SharePoint servers too to resolve the issue. Again, there is no mention of this in the KB article. Then when I tried to install the hot fix on our 4 SharePoint servers, it went thru fine on 1 server but “failed” on 3 of them. So to troubleshoot the issue, we decided to uninstall the original “SQL Server Reporting Services Add-In for SharePoint Technologies” and simply install the newer version. However after uninstalling the original version, we were unable to install the upgrade OR the original version leaving our SharePoint installation broken! Then after doing some research, the support person found the following method (http://msdn2.microsoft.com/en-us/library/aa905871(SQL.100).aspx) to run the install from the command prompt:

1. Run the original setup as follows: msiexec /I SharePointRS.msi SkipCA = 1
2. Navigate to the %TEMP% folder and run the following: rsCustomAction.exe /i

Please NOTE that the verbose messages at the end of the 2nd command will say that the install failed. But it actually goes thru!

After doing the above on 1 server, we realized that there was really no need to uninstall everything and re-install because even though the upgrade said it “failed”, it actually went thru. So we did some testing on our remaining 2 “failed” servers and they were actually fine. To make sure the problem was really truly fixed, I restarted all the SharePoint WFE servers in NLB, turned IIS off on each of them except 1 and hit the web-site to ensure the problem didn’t occur.