Error 1325

Hello
I recently installed DNRgarmin, a GPS/GIS utility on thumb drive j: with no problems, ran fine. Now trying to install on hard drive with following: "Error 1325: PortableApps is not a vaild short file name." I see this is a generic problem for flash drives and fixes point to the registry and I've tried several approaches including repairing and searching the registry with no luck. I was able to install a previous version of DNRgarmin, but would like to be able to have the latest, plus I'm worried about future problems with other programs.
Any comments appreciated.
Andrew