Same or similar problem here.
Every time I open desktop manager, I get the following windows installer error message:
"The feature you are trying to use is on a network resource that is unavailable."
"Click OK to try again, or enter an alternate path to a folder containing the installation package 'BlackBerry 7130.msi in the box below."
I have searched my hard drive and that file does not exist.
I have uninstalled desktop manager, downloaded the latest desktop manager s/w and reinstalled. Same problem every time. I am at a brick wall .... h e l p