Cognos 10.1.1 refresh pack and SharePoint 2010

[bdbits]

We have had 10.1 installed and working with SharePoint 2010 web parts for about 6 months now. Over the weekend the refresh pack was applied. Now the web parts are not working in SharePoint 2010. There were no changes on the SharePoint side. The web part says:
  Unable to process the request.
  invalid string position
  A more detailed description of the error that occurred can be found in the log."

So of course we looked in the logs. Which said "invalid string position". Wow - great logging there. So then we ran an authentication trace which had:
  camAuthUnrecoverable
  Unable to authenticate a user. Please contact your security administrator.

Ummm... If you are not familiar with them, the SharePoint web parts use a shared secret provider bundled with Cognos. Once Cognos determines that SharePoint knows the correct secret, it trusts SharePoint to have done the authentication of the user, but Cognos does do a lookup on the passed-through userid to find capabilities, roles, etc. I won't go into the gory details of how this works, but will note this all worked fine before the refresh pack. Something broke, we are just having a hard time determining what. I tend to think it is when SharePoint is passing it's shared secret over, but because it is all encrypted this is difficult to check.

So I guess I am wondering if anyone else ran across this and what did you do to fix it. I will call support if we have to but my experience is that they know next to nothing about these integrations and basically tell you your SharePoint is the problem, though nothing they do really says where the problem lies. We've always ended up having to make this stuff work by ourselves, sad to say.

If we figure it out, I'll post the solution.

[Grim]

Did you install 10.1.1 RP1 in the same directory(On top of) the existing 10.1 install you had previously?

If yes, back everything up, uninstall it all and delete the files/directories. Start from a fresh 10.1.1 install from scratch.

You can not install 10.1.1 on top 0f an existing 10.1 install.

[bdbits]

No it was an uninstall/reinstall as laid out in the refresh pack documentation. Our admin is very good about that sort of thing.

If we cannot resolve it by Friday I think we'll call support. I suppose I might get lucky and get assigned a knowledgeable support tech. Based on past experience when calling about SharePoint integration, the odds are not in my favor.

[Suraj]

If it is a fresh installation, were all the settings replicated exactly?

You have to re-copy the dll/.dwp files from new version of cognos to IIS http root directory and modify/update the files that need configuration such as trust security file (wss_custom...) and web.config file.
There may be differences in those files that could be causing the issue.
We are still in 10.1 so can't test whether RP1 breaks sharepoint integration or not.