The FieldPoint Ethernet modules (as well as LabVIEW - DSC and Lookout) utilize a propietary National Instruments Ethernet protocol. The protocol is not published and is currently restricted to Windows based platforms. There are several interfaces that allow one to communicate using the proprietary protocol; including NI FieldPoint (which has interfaces for LabVIEW, OPC, LabWindows/CVI), Lookout, LabVIEW - DSC, DataSocket, and (I think) a ComponentWorks module). Even though several of these interfaces are multiplatform, the ethernet support will only work on Windows based platforms.
Whereas the FieldPoint ethernet protocol is proprietary and closed, the protocol for the serial modules is open and published in the FP-1000/1001 Programmers Reference Manual. You can build your own multi-platform solution that way. Alternatively, you can use the FP-20XX series of RT Controllers and embed a LabVIEW RT program that publishes the channel data in your own format that you can write a non-platform specific interface to.
Regards,
Aaron