SPFarm.Local.Solutions.Add - Exception - "Access Denied" - sharepoint

Question

Here is my code snippet:
SPSecurity.RunWithElevatedPrivileges(delegate()
{
SPSolution newSolution = SPFarm.Local.Solutions.Add(#fullPath);
});
The stacktrace and innerexception give no further clues. The Exception.Source says Microsoft.SharePoint.
SPFarm.Local.CurrentUserIsAdministrator() returns TRUE for the userid.
The userid is in the Farm Administrators group.
Any ideas?
EDIT
I have changed my code to the following and still get the Access Denied error:
private void AddSolution()
{
SPSolution newSolution = SPFarm.Local.Solutions.Add(#fullPath);
}
SPSecurity.CodeToRunElevated elevatedAddSolution = new SPSecurity.CodeToRunElevated(AddSolution);
SPSecurity.RunWithElevatedPrivileges(elevatedAddSolution);

Answer 1

Your main problem might just be that you are not DBO of a sharepoint database (_Config if I'm not wrong). Adding a solution to a farm is something that require more rights than just access to the farm.
Be sure that the user running this is Farm Administrator and DBO of the proper database.
If you still have problem... try running
stsadm -o addsolution -filename
"myWsp.wsp"
If you have the proper right, it will give you the proper error.

Answer 2

Have you tried declaring the delegate outside of the call to RunWithElevatedPriviliges?
Edit: Ignore below as you appear to have checked permissions.
RunWithElevatedPriviliges will use the identity of the application pool which SP is running under. Have you ensured this account has sufficient privileges in your environment?

Answer 3

I do believe that the issue you are having is due to the fact that you are using the static member to access the SPFarm object. I think that it is similar to running the SPcontext static class which will still run under the security context of the logged on user and not under the elevated privledges context (which is the local application pool identity).
Try this instead inside your delegate:
SPFarm spFarm = SPWebService.AdministrationService.Farm;
SPSolution newSolution = spFarm.Solutions.Add(#fullPath);
EDIT:
Since the above didn't help then your issue probably has to do with database permissions to the config database. The RunWithElevatedPriviliges will run under the application pool's identity that the code is running under. Adding a solution to your farm affects the configuration database so your application pool identity will need access to the config database. As a test try adding the app pool identity to the config db and give it dbo permissions. If that fixes the issue then you will need to find the minimum amount of permissions that each of your app pool accounts will need to add solutions (do not leave as dbo)