"Unable to update local resource group" error

Question

Hello,
I'm having a problem updating one of my local resource groups in RD Gateway Manager.
We're on 2008 R2 SP1, and have a gateway in between us and another company. When a user needs to access their computer in the other company, we add the machine to the local group, and the account the AD RAP group, it works fine.
However, every couple of weeks, it will not allow me to update the local resource group for computers. I receive the error "WMI Failure: Unable to update local resource group" ..and apparently google cannot find another instance of this error happening -
no results at all - very odd. So the normal fix is to just recreate the RAP.xml file, then add the machines in again, but this is not a good enough fix long term, plus it misses the machines that are switch off when i recreate.
Also - this will be logged in eventvwr TerminalServices-Gateway  
"The resource group "MY GROUP NAME" could not be updated. The following error occurred: "23106". To resolve this issue, ensure that you have configured resource group settings correctly and set the correct value and permissions for the RAP.xml file and the
RAPStore registry key."
Google also cannot find anything for that error, OR that 23106 error code - I cannot get results no matter what I do. It cannot be permissions as I've checked them, and it works for a bit. I've ran the WMI diagnostics, and they're fine, no different to any
other server in the environment. 
I've also checked these forums and there is nothing on there. Does anyone know the relevance of that error code, or where I can check it out?
Cheers,
Jon

Answer 1

I can confirm ..MPIN..'s solution fixes it.
I had the exact same problem; I'd recently added a new server, and stopped the old server before decomissioning.  Adding the new serer to the TS RAP policy server didn't work and generated the OP's error.
I removed the old server name (which was not pingable) and the group COULD be updated.
Really crappy error handling - this is a defect and should be fixed.  A proper error would say "Not all machines in this group are valid, please remove the invalid entries" OR simply allow 'ok' without double checking (after all, the names are checked
when adding).
So often we accept shoddy software by proposing work arounds as 'the fix'.  The actual fix is to fix the software to be more descriptive and/or handle errors more gracefully.
== John ==