DRIPS works in both Windows and Linux.  We haven't officially released the Linux version yet but it has been tested in Linux and we are waiting to see what kind of demand there is out there.

Regarding the cannot POST error, we are using bit-pay and they seem to have a problem with their website right now.  That error comes from their site.  If someone knows of a better method please let us know.  It was working a couple of days ago.