The Washington Post article explicitly refers to Mac users (because of the preponderance of Mac users in the natural sciences, I imagine), but the problems remain for Linux users as well. I have never had to use this system, and since the NSF allows for submission via FastLane as well, I doubt many of my readers have, but I find it rather amazing that the government felt the need to design a special application just to allow researchers to connect securely to the main funding servers.
Update: Dave Schroeder of UWisc says:
The University of Wisconsin has released a standalone package for using Grants.gov on Mac OS X as a service to the community. The package uses Citrix client software and a special settings file to access the central Citrix server provided by Grants.gov, allowing users to access and use the PureEdge software via the remote Windows machine running Citrix server software: