I sorted it out, since I had the same error when reinstalling MPS at a clients site on the same machine.
Before you do the upgrade/install you have to uninstall any existing version of MS Office.
MPS install is checking some registry entries which are not deleted when you do a MS Office uninstall, so it thinks office is still installed.
Manualy remove any keys containing word.application and excel.application, and setup can continue.
The object reference not set error is a generic programming error that indicates that the value for something was not set. This can happen alot of ways, but I would bet you're missing a file somewhere it expects there to be a file. Check the prereqs.
I am not familiar with that particular error message however I have some things for you to try. Also, if these option don't resolve your problem then please contact your Xerox technical support team.
1. Before you re-install clean out the windows Temp folder
2. When you re-install make sure you are logged in as the administrator
3. When you run the Mobile Print Solution installer, right click on the installer file and select "Run as administrator"
Let me know how it goes
Tried to upgrade our MPS v1.5 solution to v2.5 last day.
After deinstalling MS Office and succesfully installing the prerequisites, the actual installation fails with following message "Object reference not set to an instance of an object".
Installing on a Win7 x64, with .NET 4 and the latest windows updates installed.
Anyone who knows a solution? Google hasn't been my friend in this one, besides it's learning me it might be a buggy written code.