While National Instruments definitely recognizes that Ubuntu is the most popular distribution overall currently (http://deviceguru.com/linux-distribution-popularity-trends/), we find that the majority of our enterprise and test customers using Linux distributions are using Red Hat. We continually survey existing and potential customers of National Instruments products and when Ubuntu gains more acceptance within that community then we will definitely revisit the idea of official support of Ubuntu. Here are the four distributions we currently do offically support (http://digital.ni.com/public.nsf/allkb/4857A755082E9E228625778900709661?OpenDocument). That being said there are many customers that use LabVIEW on Ubuntu just fine but it's just not officially supported.
Currently LabVIEW only has support for Mandriva, RedHat and SUSE Linux. What's even worse, only 32-bit versions of those are supported. Today, 64-bit linux installations are on huge raise, and Ubuntu is getting more and more popular. LabVIEW Linux support should be expanded to include Ubuntu, and 64-bit versions are needed.